I want to have a BBL done as well as a rhino. My question is if both can be done during the same operation?

I would recommend separating these surgeries for the reasons you mentioned.  Also, depending on how involved, the surgery time may be lengthy.  About 4 weeks between surgeries would be my recommendation. 

Yes, both procedures can be done simultaneously or these procedures can easily be staged. I would speak with your plastic surgeon about this possibility if you feel it is necessary.