I'm assuming str/int/con for Kai/Wizard and str for the paladin?

I play to play through BG:EE into BG2 EE so I guess I'd dual in BG2?

(I'm playing with friends that's why)

If you are power gaming/min-maxing, then you should go STR/DEX/CON/INT for the Kai-Wizard, and either STR/CON or DEX/CON for the paladin -- note that paladins are hard to roll good stats for, as their only viable dump stat is INT, but even that is important not to min. in BG2. Paladins will always have sub-par stats compared to fighters because of their minimum stat requirements in WIS/CHA at character creation.