[Aerich]

Well, it's not quite a powergamer's party yet. You need 18 Dex (or better) with every character, because it affects your AC and ranged attacks.

So I would make the following stat alterations:

Paladin - 18 Dex, and drop Wis to the pally minimum (13). Strangely, you will still get access to 6th lvl clerical spells despite a 13 Wis. This works for paladins, but not for clerics.

Illusionist/Thief - decent, no changes necessary. I don't quite understand the 13 Wis, though. If you are inclined to re-roll this character, you could drop the Wis down and put extra points in Str.

Fighter/Mage - fine. Too bad the Str isn't higher, but it won't make any difference if this character is mostly an archer. If you put this character into melee, make sure you cast Strength for added power.

Fighter/Cleric - sorry, 16 Dex is not enough. Compared to 18 Dex, a 16 means your AC is 2 points worse. Seriously consider a R/C.

Bard - get that Con up to 16 for +2 HP/lvl up to lvl 10. You also need at least Str 12 to use longbows. Buy the spell Friends and give it to your bard for when you need to buy expensive items. If you have extra stat points to allocate, consider putting your Wis up to 13 - there is a bard-only item that requires Wis 13.

Fighter/Druid - with 12 Dex, your AC is 4 points worse than if the character had 18 Dex. If you want this character to be able to fight in melee and contribute with ranged weapons, 18 Dex is required. You don't need 18 Cha with this character, as talking/buying should be covered by the bard and/or paladin. I'm sure you're having trouble rolling up this character, so drop the Cha down to the lowest it will go (15). Dex, Con, and Wis should all be maxed out, Int can be minimized, and Cha can be minimized as much as the class will allow. If you have to, Str can be dropped, as there are plenty of potions and some Str-increasing items later on in the game.