Yes, feed frozen if you have to. At least give it a try first. If they are acting as hungry as you say then I am sure they would accept frozen/thawed. (f/t) I'm not sure if keep them in the same room as your rats is exactly stressful for them, but I -do- know that my boa tends to be very aggressive when she can smell her food dethawing in the same room. Maybe just move them to another room and see how it goes?
I myself get my frozen rodents over the internet, but I'm sure you can find them at a local petstore. Petco in my area has frozen rodents for sale. Call around and find out.
Most older ball pythons usually don't bite, but you don't know if these two were handled a lot either. There is no guarantee they will not be bitey if that's the case. You usually tame an anima, such as ball pythons, down over time with some decent handling. It'll all just take patients.