as for that black screen thing.I had the same problem at the same place,and also,it will happen more times within the game too,so be prepared.

Anyways,the only thing I found that works against it,is to use the emulators save state button(F5 if I remember correctly) just before the cutscene starts,then when it hangs up(if it does),press the load state button(F7).and try again.I found that most often it doesnt hang up after you try a couple of times. Also,about those graphic problems,maybe I'm wrong,so if I am somebody correct me,but I think that some of them are hard to get rid of due to the fact that the game simply doesn't work flawlessly as a rom for any N64 emulator.And as was mentioned,some plugins might fix some of the bugs but create new ones.