1) Nope
2) I don't think you're allowed to make money through a graal server. Dunno about donations
3) Well, you can pretty much script Alot until you come to limitations of your own skills, what gs2 can't that other languages can etc. You can do 3d but you need a 3d server for that.
4) I don't think so (For making gmaps?)
5) Yes, GK comes with the same engine, but has some predefined objects and such for their mud system they have, unless it's the same. Only think to do would be making a gmap with terrain and custom bodies :P
Hope that answered some of your questions
