Depends on why you want to be a saint.
If it is from a love of God and desire to do His will, then yes.
If it is so people can say “Look at how neat he was”, then you have a bigger problem.
No, it doesn't. Becoming a servant, indeed a slave of God, abrogates your right to expect anything; it has nothing to do with your status, promotion, position or honor in God's world. God calls you and you accept to serve. No other condition exists. If you are willing to serve God unconditionally, then let God decide who will be a saint. Don't expect it in return for your service.
If it is from a love of God and desire to do His will, then yes.
Nope. It's not a contract. It's a submission.