1) Great idea.
2) No. It could be horrible because it can be stuck because heavy sine and heavy cosine calculation things.
3) No. The main target of playing this kinda server is selling goods / services, not killing zombie bosses, 20K is enough.
4) Great idea.
5) There's already a shop in menu.
6) No. Arresting a killer is giving a lesson how to play, do not kill anyone. Imagine player with > 10M money and keep killing players, players start leaving the game and polices can't do anything.