I saw you requested help on the choose leader and civ thing. I decided to give it a shot (in C++). Will update you later whether I succeeded.
Re: isn't working: You need feudalism (for vassals), too, and also the puppet state gameoption (I think that should be on by default, since you probably don't download this to play without that gameoption )
Re: isn't working: You need feudalism (for vassals), too, and also the puppet state gameoption (I think that should be on by default, since you probably don't download this to play without that gameoption )