I believe that you should keep the temps constant, even though I do hear of people dropping for night times. You will probably get a better feeding response each week if the temps. do not fluctuate at all. Breeding may be another story, but for general purposes, I would keep a constant temp in the enclosure for the BP's.

Never ever house two Bp's together. They compete for the best spot and may go off feed because they are incredibly stressed in that situation. There are many threads on why not to house together. Check it out too much info to list here.