"Sharpshooter and GWM give a flat always-on +1 damage bonus to the respective weapon types, plus their side benefit. No -5/+10"

"Feat Changes
-5/+10 feats (GWM, Sharpshooter) instead grant a flat +2 to damage with the appropriate weapon. Other benefits still apply.
Polearm Master’s bonus attack only works if you’re wielding the polearm in two hands.

Items
Quarterstaffs are two-handed only."



Just a little thing - you say GWM/SS add a flat +1 to damage earlier/above and then change to +2.

So if a 1/4 staff is 2 handed, can you PAM BA attack w/ it?

Are the allowed race's subraces allowed (shadar kai for example)?

" Magic Resistance
Items or abilities that grant Magic Resistance give the creature +1 on saves vs. spells per 5% MR they would have granted. “Magic Resistance” as flat advantage on saves vs. spells doesn’t broadly exist any more.
Magic Resistance cannot be reduced below +0."

Isn't the normal MR = 50% so +10 on saves? How does that math work?



I don't know anything about BGII, but your rules seem very well thought out and I expect it will be a heck of a campaign. I especially like the mage slayer buff.