I think this should be divided into categories if it is going to work because staff members of different types have substantially different jobs and basing it on one set of criteria may not allow for fairness.

It will be based on how well they do their job and not what their job is. What their job is is of no matter , how well and what they contribute to the server however is. For example a FAQ can contribute much by being on and helping all those who need help of the server whether it is Staff or Player. Players are more inclined to come back to a server if there are Staff who are friendly and helpful even though the content of the server may not be so great. This goes along way to help a server with players.

If you're staff on two servers I don't think you should be eligible for either. It's obvious you're just splitting your talents and half-assing for both, when you could be full-assing for one.

Of course it wouldn't give you more chance, 2 people get up for vote so you'd only be once. Also im sure they would say if you have been nominated already to give it a better competition. Else im sure someone could get nominated 8 times.