House rules for a new player's Ranger character; are they balanced?

Question

I've managed to convince my GF to try out a simple campaign. She is new to tabletop gaming. Knowing her, I decided to have her play a ranger with a pet (she loves her dog, a lot). I designed some house rules to make things like action economy simpler for her, also not wanting her dog to suddenly die to a random crit from a bear. I was wondering if some of the house rules will make the game unbalanced.

Rule 1: She will be able to swap between her Bow and Sword at the start of every turn.

Rule 2: Her pet dog will not die when at 0 hp, but rather be treated like a PC. It will have death saving throws and she will be able to stabilize it with an action.

Rule 3: The dog will always go after her turn and will follow her latest command. If no command is given, it will stay by her side and ready an attack for anyone who tries to attack her.

Rule 4: She can command the dog as a free action.

This will be a short 2 combat campaign where I'm just introducing what it's like to play RPGs. The only other player is her sister, who is playing as a spellcaster.

Answer 1

Your house rules are slightly weaker to the already published Unearthed Arcana: Revised Ranger Beast Master, except for rule 2, which isn't game breaking anyway.

This 'Rule 2' is already covered in the PHB page 198, Monsters and Death:

...and special [NPC's] are common exceptions, the DM might have them fall unconscious and follow the same rules as player characters.

Therefore, it has already been deemed balanced.

You can use the Unearthed Arcana version and it'd be satisfying and simple to play. If you are worried about the complexity of correctly assigning all the statistics and numbers for the animal companion, I suggest you do that for her ahead of time. With the Animal Companion statted up by you, all she has to do is take control of it while in combat, like having a second turn.

Answer 2

For #1, see my question here about that issue generally; the consensus is that it will make combat less of a choice since all archers are also melee combatants with no consequence. I'd suggest maybe not doing this, but it's not a huge problem if you do it anyway; maybe see how much of a problem it is and implement this if not doing this is impacting your fun.

For #2, this should already be the case anyway, since this essentially counts as an important NPC, and PHB pg. 198, under "Monsters and Death", says:

Mighty villains and special nonplayer characters are common exceptions; the DM might have them fall unconscious and follow the same rules as player characters.

For #3, not issuing a command; the spell Conjure Animals (PHB, pg. 225) says:

They obey any verbal commands that you issue to them (no action required by you). If you don't issue any commands to them, they defend themselves from hostile creatures, but otherwise take no actions.

which sets a precedent for beasts defending themselves (which could easily be extended to protecting the ranger so long as they only did so whilst remaining by the ranger's side), so I'd say what you propose in your question seems fine to me. (Thanks to @V2Blast for reminding me of this quote)

Finally #4; there are a few dnd-5e questions about changing how this works; the most relevant of which is likely this one (again, thanks to @V2Blast).

I can say that when DMing for my partner (whose first character was also a Beastmaster ranger), I suggested that it uses up her character's Bonus Action rather than Action, which means it still has a cost, but not one has harsh as using up an Action. Commanding the beast as a free action removes any cost, so I'd recommend a Bonus Action, which worked well for us and felt balanced (i.e. want to cast Hunter's Mark? Your beast does nothing this turn).

I know that the quote above from the Conjure Animals spell says "no action required by you", but in this case you've already paid the price of a spell slot, and it's a 3rd level spell, which for rangers specifically requires them to be level 9, so it's a big difference from an "always-on" class feature that you have from the level 3 Beastmaster archetype. Hence I'm sticking with my advice of having commands cost a Bonus Action.