Good luck with that...pretty much all rat pups are cute, IMO. I had pet rats long before I ever got into snakes, & raised a whole family of them. But I doubt you can raise that one to be healthy from this stage, so it might be kinder to get "un-attached". Not only that, but having a pet rat that your snake will smell on you may get you bitten.
As far as your snake not liking lights, mostly that's just directly overhead. Don't worry about your normal room lighting, day or night. But any lights used on their cage should be dim though, & preferably red or black bulbs. BPs are basically nocturnal snakes- they don't want to be under a bright "basking" light the way many lizards are kept.