Modding in Icewind Dale 2

This thread is to discuss the possibilities of modding Icewind Dale 2, the Infinity Engine game most notorious for having lots of hard-coded stuff that makes it difficult to mod. Since barely anyone mods this game, especially recently--the big mods for IWD2 are all very old--there's not a lot of information on how to do it. I wanted to share some of my findings and hopefully others in the community will be able to show their own insights.