1. Some people with single snakes just keep them in a tub; however, i think a glass aquarium or PVC enclosure would be more probable. Most new people to the hobby start out with their first snake in a glass tank, i know i did.
2. All of mine react the same way to everyone. Bps arent the smartest snakes so they dont have the brain capacity to think "oh thats the one that feeds me, i dont wanna hiss when he picks me up" or anything like that.
3. No it isnt advisable at all to let them roam. Id never let any pet snake roam my house. If a bp escapes outta its enclosure it seeks out a place to hide. A good hiding spot for a bp is a dark and tight place. I you read some of the escape threads on here some people have found their snakes in some really crazy places.
4. Bps arent really the best swimmers. The only reasons that there are to soak them are to get poop off them if they made a mess or to get off stuck shed if they had a ba shed. They dont need baths and dont really enjoy them that much.
5. Bps arent killer snakes that will get out and strangle and eat your child in the middle of the nite. Most weeks i cant get all of mine to eat their rodents, i cant imagine they'd go for a human child instead of a juicy rat lol. Also a bite from a bp isnt bad at all. The scary part is the strike bc it happens so fast.
6. Some are friendly than others. Its pretty rare to find an aggressive bp. Some of mine are friendly and curious and others are more nervous and headshy. If i want to introduce someone to my snakes and let them hold one i would pick one of the friendly ones. Not bc im afraid a nervous bp would bite or anything, but bc id be afraid that the visitor would get afraid of any nervous behavior that they exhibit. When my cinni girl hisses and flicks her body at me i dont bat an eye at her bc i know shes bluffing. But to someone who has very little experience with snakes that could be seen as a sign of extreme aggression or something. I think its cute though lol.
I added numbers to make it easier to answer. I hope this helps!