Naturally, you'll be able to play our mods on BG2EE: from what I know, most BG2 mods will be playable from day one just as they are now, and we'll do our best to adjust portraits/journal entry code/item descriptions to make BG2EE experience more comfortable(for my mods, certainly, for other, non-maintained ones, we may request help). I'm not sure how to do it, yet, but once BG2EE is out, things will probably be clearer, especially with the examples of converted code. And, yeah, I've played BGEE already.