I think you have to pay 10% plus closing costs but can arrange with your guide to have time to pay off the rest. You can make that initial payment on more than one card but do need to do it at once. Later you just call the guide or the billing and they can charge different credit cards.
I know people say 90 days but the most I have gotten is 60 days. People also push the 6 months 0% on Disney Visa which is fine if you already have the card. If you don’t have it yet another credit card that offers at least a year at 0% would be a better option; especially if you are getting cash back instead of Disney dollars.