-I agree w/almost everything in your post except the stuff on Aerie. Though its worth it to mention that she, juss like almost every other joinable NPC in the series, is an acquired taste. There's no universally liked joinable NPC in the series, except perhaps Imoen. And thus I'm not contending your dislike for Aarie, but I personally think she's fantastic; it's good to have someone who remains that close to their own soul to balance the dark adventures that the PC finds him/herself tangled in.
-What I noticed is that Jaheira is the most experienced party member I have in BG1, her xp total even exceeding that of my PC. And given that it's also her first time on the road, from a RP standpoint, it's like she feels she has to be the 'momma' of the party, and the stress is getting to her. Hence her having that way of thinking in BG1. And then they did an awsome job of rounding her out in BG2.
-Yeah Ajantis is the most annoying paladin you'll meet in the BG series. Not trying to stick up for him, but it seems as though his overt pride & dedication are rooted in being endorsed by renowned paladin Keldorn, as he's too focused on his task and too inexperienced in the world to know how to treat any non-paladin (& those who share similar characteristics) with appropriate decency.
-LOL! Xan a bladesinger? Wow....that's very hard to imagine, to say the least. IIRC, moonblades can be wielded by non-bladesingers, so long as the blade chooses it's owner. Why that particular moonblade (which is +3 to hit, +3 to damage, and gives 50% fire resistance, thus making it the most powerful sword in BG1; a moot point, given the wielder) chose Xan, remains something of a mystery.
-I find Anomen to be alright, most of the time. One things for sure: he's one hell of a fighter/cleric. As far as his personality goes, juss get Jan Jansen in the party with him. Trust me, that'll certainly make Anomen all the more tolerable. :;oD
-I once saw it written a long time ago, that Khalid is the 'realest' joinable NPC there is, and I tend to agree with it. For all his perceived cowardice, it's good he knows when the odds are stacked against him! Ha!
The people I usually travel with are:
BG1; I used to enjoy having Kivan, Dynaheir, Coran & Yeslick for significant amounts of time travelling w/my PC, Imoen, and two more MP created party members, but now on my current playthrough, I'm going with my favourite party of PC, Imoen, the two MP created PC's, Minsc changed to pally and Jahiera changed to a Cleric/Ranger. Though I don't give Minsc a Lay on Hands ability, don't use his berserker rage, and don't give Jaheira a racial enemy. I also take away Minsc's racial enemy upon making him a pally.
BG2; PC, his MP created right-hand man, Imoen, Aarie, Jahiera & Minsc like how I got'em in BG1.(BG2 Spoiler ahead:) I like rotating Imoen's spot in Chapter 2 & 3 w/whichever NPC is most fit, from a RP perspective, for the quest at hand, or juss go w/Jan Jansen. And I take Yoshi with me in Chateau Irenicus & again when it's time to go to Spellhold.