Don't worry about the 28-pt build for Drow. They can easily end up ahead of other races when you go for a combination of any two or three of dex, Int, and Cha.
I took a look at your proposed stat spread, for comparison, here's how it could look for a Drow with 28 points available.
str - 10
dex - 16
con - 14
int - 16
wis - 10
cha - 12
You end up 2 ability points ahead (here in charisma) despite having 4 fewer build points, that's because every ability increase only cost one point each.
Personally I'd leave wisdom and charisma at their base stats, and raise dex or int by another 2.
The additional case for Halflings (beside Dragonmark of Healing) is that they're short. Why's that important, you ask? Because being short means it's a lot easier to line up enemies for Improved Precise Shot. Taller races will often enough fire above some enemies, or hit one only to find that their arrows/bolts are now stuck in the ground and the rest of the enemies that were so carefull lined up aare completely unharmed. On a first-life Drow this won't be an issue, though, your character only starts getting taller once you reincarnate them.
Rule of thumb is that you can get away with doing two things well, but if you try to do ranged damage AND melee damage AND casting, you'll overextend and end up doing none of them well. There just aren't enough feats for all of it. Ranged damage and supporting casting was how I played as an Arti the last time, that worked pretty well.
To answer your question, a "splash" means taking a few levels in another class to gain some benefit or to augment some area where your main class is weak. Like, in your case, you could splash two rogue levels for evasion, that's the most common splash in the game anyway. You could also go for a "deep dip" and take 5 or 6 levels of rogue to gain access to the full mechanic tree and the first 3 core abilities there, the downside of deep dip would be that you get access to at most one level 6 spell.
And while we're on the topic of downsides, the downside of playing a half-elf is that they're the ugliest race in the game.
As for what feats to take. First you need to figure out what you want to mainly play as. Do you want to be a caster? Ranged damage dealer? Melee?
And as for Skills, I can tell you're overextending. There are some skills you will want to max out.
Firstly: Search, Disable Device, Open Lock. Those are the most useful skills whether you're soloing or playing in a group.
Secondly: Spot, UMD. You can skip Spot if you know the game extremely well and remember where all traps are, if that's not the case, definitely take it. UMD will let you use Wands and scrolls, especially useful for healing.
Everything else is pretty much a matter of preferences. But try to play to your class' strengths, you're paying double for hide, move silently, and Jump, and will always be lagging at least 50% behind a class that gets those skills. Artis may be able to disable traps, but they're no sneaky rogues, they have other strengths instead.
Also, Concentration is not all that important unless you're a Monk. Most of the time you either don't get hit and cast that spell, or you get hit for so much damage that you fail the check anyway. Furthermore, quickened spells always succeed (unless you get tripped/stunned while casting), so if you take that you won't need Concentration anyway.
Your initial spell selection looks good. Artificers can also permanently learn every spell in their book from scrolls and switch them around in taverns and at shrines, so you can play around with your setup and see what works there.
All players are KOS in all quests and Wildernesses, no exceptions.
The Dilettante feat does not improve any skills, it only gives you 1d6 sneak attack damage. Your skills can be equally high no matter what race you take.