I'm going to challenge your premise a bit - why not drop XP-based levelling altogether and use milestone levelling instead? In my time as a DM and a player, I've found milestone has a few advantages:
Less resource management. Counting all your XP is a bit tedious.
Less DM work. You can tailor encounters that are fun and play to your party's strengths, and ...
Carcer and I can independently verify that all your math checks out.
That said, take a deep breath. I doubt this question was prompted by your lack of faith in your own math and reading skills, but instead by your DM's insistence that this encounter wasn't deadly, and this much bold formatting and all-caps in a question (prior to style edits at least) makes ...
I'll step through each of the classes individually, but first the broad strokes:
[Most] Spellcasters will fare much better than everyone else
The main check on the power of a Spellcaster is their limited resources. If a Level 9 character uses a 5th Level Spell Slot, that's it: that's the only fifth level spell they'll get for the whole day. Wizards and ...
At level 2 (on average).
CR tells you the upper maximum difficulty of the monster, assuming a party of 4.
Since the Mimic has CR2, it's a challenge for a level 2 party.
That being said, you can easily adapt this.
After a boss fight, the level 3 party is low on resources, and finding a mimic instead of loot can be a challenge for them.
You were just over "1 day's XP budget" (five minute adventure day)
In the Basic Rules p. 166/DMG p. 84, there's another table that lays out the estimated "adjusted XP" for an entire adventure day. For your party: 7th /5,000/ x 4 = 20,000. (Your adjusted XP calculation was correct at 23,400).
The usual adventure day is designed with "6-8 encounters of ...
Surprise is very much up to the GM
How does surprise work?
The section on "The Order of Combat" states:
1. Determine surprise. The DM determines whether anyone involved in the combat encounter is surprised [...]
The section on "Surprise" states:
The DM determines who might be surprised. If neither side tries to be stealthy, ...
Yes, typically award the full encounter XP
The Monster Manual says you gain the XP for "defeating" monsters. Typically this means killing them but, as it also says:
...the DM may also award XP for neutralizing the threat posed by the
monster in some other manner.
Now, I can't speak for other groups or DMs in order to tell you what is "standard", but ...
Either is fine.
Assuming your d20 is fair, either a 1 or a 20 will occur 5% of the time, or "1 in 20."
The DMG, one paragraph later, lays out a procedure: "when an encounter check is indicated, roll the appropriate die and, if a 1 results, an encounter takes place."
This, however, is mathematically no different than saying "if the highest value results" ...
Every three turns, unless the DM decides otherwise
This answer presumes that the only material you are using as a reference are the PHB, MM and DMG.
If you also have the Holmes Basic Dungeons and Dragons book (which
was published as a precursor to AD&D as the game evolved) the answer
is in that tome.
How did I come up with that answer from the DMG? (...
I'm not certain that describing the fight as "Deadly" for your level is wholly inappropriate; however, there is some Math we need to knock out first.
Frost Giants are weaker than their Challenge Rating would suggest
In the Dungeon Master's Guide, the advice for creating custom monsters provides advice on how to stat creatures based on what their Challenge ...
Every encounter with an intelligent creature can be a social encounter
In some cases, it is really smart for your PCs to first parley before deciding to get violent. You need to discuss with your players what their operating mind set is: when they meet a bunch of humans or humanoids (you don't need to say "you see seven bandits") what is their first ...
Attacking the camp is never the only option
There are a lot of factors that go into determining the balance of encounters in D&D. The CR guidelines, players skill, party composition and often the DM gut instinct all play a role. Without being in your DMs head or even at your table we can't tell you if they are stacking things against you. However we can ...
Maybe, maybe not
This party make up is far from ideal, but it might be doable.
How doable will depend on how much guidance they accept from you, as the DM.
The main problems
You know this already, there is very little healing in the party, and none at level 1.
There are a couple ways to mitigate this, however.
Give them healing potions.
"Mathematically", this is beyond a "deadly" encounter, but that doesn't mean the DM planned on killing you.
Using the tables in the DMG (page 82):
A "hard" encounter for 4 level 8 characters would have monsters worth 5600 XP, a "deadly" encounter 8400 XP.
20 "minions" = 2000 (at 1/2 which would be very beefy for their CR seeing as other 1/2 CR has around ...
The question is broad, so I will be giving a broad answer, without entering the specifics of each one of your sub-questions (as I feel that actually requiring an answer to each would result in closing the question). The general answer is: reliability gets punished, bursty stuff gets rewarded. With that in mind...
Which classes are most affected?
You will probably struggle with the adventure as written, because of the newness of the players as much as the composition of the party.
I ran Lost Mine of Phandelver for a brand new player, as her first experience with D&D -- or indeed with any roleplaying game. She wanted to play a genasi wizard. This was a duet experience (i.e., a DM and one player), ...
Xirema and KorvinStarmast have done an excellent job in analyzing your particular encounter, but I want to get a bit more into encounter design and the tools for calculating difficulty.
In my experience as DM and player, I've found that the encounter calculators are really not all that useful in terms of what's reasonable during a day. ...
Most likely not
In fact, I can say with reasonable certainty that they won't even really survive the very first encounter "without too much trouble". First level characters are notoriously squishy and being outnumbered at level 1 is a very good way to get dead.
The very first encounter involves 4 hidden goblins who will very likely surprise at least 2 of ...
There are a few techniques that I've tried myself which have been effective for scaling combat challenges up or down, and they should apply to series of encounters just as well.
1. Adjust the number of enemies in combat
The action economy is a big deal, especially when enemy groups mix types of enemy to allow more possible combinations of actions the enemy ...
Make subsequent encounters harder
Disclaimer: this is based on my experience as a GM running my own adventures, not LMOP
It seems like you're afraid of giving your PCs too much power, allowing them to breeze through the end content of the module. This is a valid concern, as the players might get less engaged in the game. If you see that this is the case, ...
After having reviewed the module in preparation to DM, there are some things which stood out.
Glasstaff is given lots of treatment for roleplaying, and he's supposed to be that affable evil type of villain that invites the party to have coffee, "means no harm", and offers full tail-between-legs surrender. As a wizard, he's more of a "roleplay boss" than a "...
On a roll of a "1"
In the last paragraph on page 47 is this sentence:
When an encounter check is indicated, roll the appropriate die, and if a 1 results, an encounter takes place
Conventionally also, the expression "n in x" is usually read as meaning "on a 1 through n, on an x-sided die". For example, a gnome listening at a door for noises will hear ...
Quite A Lot
Minimum Draw: You don't have one, so anyone with an Initiative modifier of -2 or lower gets dealt ZERO cards. They don't get to act in combat. At all. That's silly and needs to be corrected.
Slow Dealing: Dealing out 3+ cards to every player, NPC, and creature will consume a surprising amount of time. No idea if you ever played Deadlands Classic,...
An encounter does not start, initiative is not rolled, and surprise is not determined, until some combatant has reason to attempt to initiate it.
For all combatants to be surprised, that must mean that no combatant has noticed a threat.
And if no combatant has noticed a threat, why is initiative being rolled?
There is an important distinction to be ...
Based on my experience running a sandbox game in OSR, Pathfinder and D&D 5:
You place some intelligent, and not uncompromisingly bloodthirsty, creatures in your marches. Most intelligent creatures care for their life and are unlikely to attack on sight without provocation. Therefore, they can be talked to, in principle.
Then it is ...
Challenging experience that will need slight changes
I am currently in the middle of playing LMoP as a first time DM for first time players with main party of:
My overall experience has been that with some changes to enemy behaviour it is quite fun for those who seek more challenging type of play.
As you can ...
A Small Guide to Socializing and Domestic Encounters
It is common for D&D 5e to lead us down a path that everything in the Monster Manual is innately a Monster. The lore behind each monster entry is pared down from previous editions and the stats emphasized. But it is not the DM's job to make a bunch of combat encounters - it's the DM's job to make a ...
When adventurers defeat one or more monsters-typically by killing, routing, or capturing them-they divide the total XP value of the monsters evenly among themselves. If the party received substantial assistance from one or more NPCs, count those NPCs as party members when dividing up the XP.
The Question is: is the encounter solved, the threat ...
Nihiloor prefers to operate in the shadows - and that means he's not interested in engaging in open combat unless it threatens his life or his goals, because player characters with a believable, supported story about a mind flayer would likely get the city watch to investigate his dealings.
Thus of course he's just going to walk away from the characters in ...
With their goblin masters gone, the wolves' dispositions toward strangers is probably at best indifferent, unless they were given a command like guard before the goblins left, in which case they'd be at best unfriendly toward anyone but the goblins. The Handle Animal skill won't improve their dispositions toward the party; that's what the extraordinary ...