Once you retake the ASVAB if you qualify for YN, you sure can put your name on the list. As for the rank thing, don't count on it. It's hard to lateral jobs over from other services to the CG. You would probably go back down to an E-3. As for the credit, they are pretty touchy about it. They don't expect it perfect without a single blemish... but no charge offs, no delinquent accounts, nothing past due, that sort of thing. All of that would have to be paid off, brought up to date and you would need to have a debt to income ratio of 30% or less.
Thanks for your time served. Good luck with everything else. Call a recruiter... what's the worse they can say, no thank you?? They don't shoot you for asking.