The real test of how "okay" this co-habbing is for them is whether or not they eat regularly (& also don't eat each other!). Yes, I know that BPs aren't known for preying on other snakes, but neither are rat snakes, & years ago, I had a beautiful pair of amel "black" rat snakes (deep orange patterns on cream) that I put together for breeding- both established adults that had previously bred to others. Both were well-fed days prior to their careful introduction (also with faces rinsed off to ensure no lingering rodent scent on either one- which is something I highly recommend you do as well), yet the male killed & tried to consume the female when I was home but briefly out of the room- they appeared to be fine together so I was shocked when I came back in the room, & I was also too late to save her.
Snakes are predators, & they don't always follow the manual... it's more likely (IMO) that being kept together may impair the appetite your snakes have, but no way to accurately predict. Snakes are not social creatures, for the most part. Just remember that for all new snakes, minimal stress & good nutrition both go a long way to ensure they remain healthy- & also that snakes are much easier to keep healthy than they are to make them well again once they're sick.![]()