So I followed the steps laid out here at this link: http://tamrielfoundry.com/topic/the-ultimate-baldurs-gate-experience/

So I followed this guide and everything appeared to be working at first, however now I'm at the first area after candlekeep (the forest) and I'm getting crazy random slowdowns with Imoen, Xzar, and the dwarf being in my party. The settings I'm using for the widescreen mod is 1600 x 900. Are there any known issues with these mods? Or maybe this is just a bad mod order (the post is pretty old, 2012ish)?

Its probably because of mods or mod order. I remember reading something about it. I will link here if I can find it.