1. Yes
2. No, You will need to feed multiple mice or larger rats
3. Rats are more better due to their larger size, but nutritionally speaking there isn't much difference.
I would look into animal plastics cages. Boaphile has terrible customer support and can really me a pain to deal with. Ap on the other hand has great customer service, and I think their cages are designed better:
http://www.apcages.com
Their T8 cage is perfect for BP's. It measures 48" x 24" x 12" (L x W x H) and can be divided to house 2 BP's in 24" x 24" x 12" sections. They also have the T1 that measures 24 x 24 x 12.