First things first, though: Crossbow Expert is borderline useless to a rogue.
Crossbow Expert has three main bonuses: Ignore the loading property of crossbows, remove the disadvantage penalty for making ranged attacks in melee, and getting an extra attack as a bonus action.
The ability to ignore the loading property is entirely irrelevant to a mono-class rogue. You never get the Extra Attack feature, so any time you use the Attack action, you get one attack. Since the only thing the loading property does is prevent you from making multiple attacks with one action or bonus action, this portion of the feat is wasted.
The second part of the feat is one you could get real use out of: make ranged attacks in melee without disadvantage. But you can also do this if you're wielding melee weapons, so not that big of a bonus, since you can draw a dagger or something for free once each turn.
The third part of the feat is one that you could get real use from, but it's just making one extra attack with a bonus action. This is a trap option, as anyone can already use Two-Weapon Fighting. It's even worse for you since you're a rogue. The majority of your damage will be dealt via Sneak Attack, and since Sneak Attack can only be applied once per turn (regardless of how many attacks you make) your second attack is strictly for the purposes of getting another chance to apply Sneak Attack if the first attack missed.
You would be served just as well by using a short sword with an off-hand dagger or dart as you would by using a hand-crossbow and Crossbow Expert. It won't be quite as effective, since you won't get your stat bonus to damage and you won't have quite as long of a range, but again, you're a rogue. The big damage comes from Sneak Attack, not a +3 Dex bonus.
Why Sharpshooter is actually good
I know you said that the calculations for the -5/+10 attribute work out to be disadvantageous until later levels, but that's not the only feature of the feat that's beneficial. Sharpshooter does two other things for you that are advantageous; one minor, one major.
First, it lets you ignore 1/2 and 3/4 cover, so if an enemy is hiding behind the back corner of the carriage you've just waylaid, you can still hit them without penalty. This I would consider a minor advantage. It probably won't come up that much, although when it does, it will definitely be beneficial.
The other benefit of Sharpshooter (and in my opinion, the greatest benefit overall) is that your range attacks no longer suffer disadvantage for attacking outside of short range. One of the key restrictions on Sneak Attack is that you must either have Advantage, or you need an ally within 5 feet of the target and (more
importantly) you must not have Disadvantage.
Hand crossbows have a range of 30/120, which means that any time you want to perform a Sneak Attack with one, you must be within 30 feet of the target, and at that point, you might as well be in melee range. With Sharpshooter, you can perform Sneak Attacks from much farther away, up to the weapon's maximum range, which will allow you to waylay targets with much greater ease, along with keeping you out of melee.
You lose out on the extra attack from the crossbow with your bonus action, which is unfortunate, but I think that the ability to trigger a Sneak Attack from up to 4x the distance makes up for it, and should you even end up at closer range, you can always make an off-hand attack with a thrown dagger or dart, since their range is up to 60 feet.
So this brings up the question: What should you take as your V-human bonus feat? And what about the Archetype?
Well, that pretty simple: for purely the highest damage potential, you want Magic Initiate and Swashbuckler.
You select Magic Initiate because from a pure damage standpoint, Green Flame Blade and Booming Blade are simply the best options for classes that don't get Extra Attack, which as previously noted, includes the rogue. You select Swashbuckler because the archetype's reliance on Charisma synergizes nicely with your choices for Magic Initiate, and also yes, that +Cha to initiative is a very nice bonus.
For Magic Initiate, select Warlock as the class, with Booming Blade or Green Flame Blade (B. Blade is preferred) as one of the cantrips, and (if you want a good ranged option) Eldritch Blast or (if you want utility) either Mage Hand or Minor Illusion (my preference) as the second, and select really anything as your 1st level spell, but my preference is Hex.
You take B. Blade over G. F. Blade due to its synergy with the Swashbuckler's Fancy Footwork feature. If you make a melee attack (with a weapon or a spell, doesn't matter) then you can walk away from the target without them getting to make opportunity attacks against you. This means that you are much more likely to be able to trigger Booming Blade's bonus damage against that target. This leaves the enemy in a catch-22 situation where they either have to move up to you and take the bonus damage from B. Blade or not move up and not attack you.
All told, you're looking at a damage calculation of 1d8(rapier) +3(Dex) +Sneak Attack +Spell damage (Per this question, Sneak Attack can be applied on the attack made using B. Blade and G. F. Blade). At level 1 you don't get much, you will get 11 damage (avg) on a hit, plus 4.5 (avg) if the target moves, although at this point, that's not likely since you don't have Fancy Footwork yet. At level 3 you get an extra Sneak Attack die plus Fancy Footwork, which gives you a nice little damage boost. At level 5 though, you get much more deadly. 1d8(rapier) +1d8(B. Blade) +3(Dex) +3d6(SA) +2d8(B. Blade movement trigger, which you're much more reliably able to trigger now) giving you an average of 23.5 damage on a hit, plus another 9 average if the target moves (either to chase you or to disengage). If you also have Hex active, then that's an additional 1d6 (3.5 avg) damage per hit.
It's important to note at this point that an Arcane Trickster can function similarly to the Swashbuckler with this tactic, as all rogues can Disengage with their bonus action, but since Arcane Tricksters don't get an additional means of applying Sneak Attack like Swashbucklers do, they need an ally within 5' of the target (which means you probably won't ever trigger the bonus damage from B. Blade) or they need Advantage, which is hard to get and maintain consistently. An Arcane Trickster will give up sheer damage output, but in return, gains significant utility. If you were to go with Arcane Trickster, I would say go with a stat line of Str 10, Dex 15(+1), Con 12, Int 13(+1), Wis 10, Cha 13
Other considerations
As you mentioned, you may be amenable to taking a feat at level 8 instead of an ASI, and then delaying that ASI to level 10. One option to consider is the War Caster feat. This feat gives three bonuses, only one of which is really useable by you, just like Crossbow Expert. Unlike Crossbow Expert, that one benefit is by itself the majority of the benefit of the entire feat.
The first benefit is that you have advantage on maintaining concentration on spells. Useful for keeping Hex active, but not really amazing, since that's your only spell with concentration, and you can only cast it once a day.
The second benefit is that you can cast spells with Somatic components even if your hands are occupied by a weapon or a shield. Not actually useful to you since the material component for B. Blade is a sword and you can already use that hand to perform the Somatic component of the spell.
The last benefit, however, is very good. Whenever you make an opportunity attack against a creature, it allows you to instead cast a cantrip on them. This effectively give you the ability to double your damage every round. If the target moves away from you, they first trigger the bonus damage from B. Blade for willingly moving away, then you make your opportunity attack for them moving away, casting B. Blade again, causing Sneak Attack damage and applying the same B. Blade effect on them again (that's how this works according to this answer to a question that asks specifically about this particular interaction).
This feat can certainly be delayed until level 10 since the chances that it can get used to maximum effect regularly aren't very high.
An Arcane Trickster rogue would have the advantage of not needing magic Initiate, and would therefore be able to take War Caster as their V-Human bonus feat
