My answer is a little late, but this is such an interesting thread. I'm still very much a newbie, but have been giving the question of how much individuality and interaction my snake is capable of a great deal of thought since I brought her home. (We got her very much as a family pet, since my son is allergic to everything.)

In our case, our female is extraordinarily mellow, friendly and curious. She will come out of her enclosure when I open it and crawl right into my hands. I do not believe she is capable of reciprocating affection, but I do believe that she has an amazing set of senses, that allow her to differentiate between various humans and recognize familiar ones in her environment. Millie will reject a f/t mouse or rat if it is less than 10 degrees off the ideal temperature and is perfectly capable if smelling the difference between a rat and my hand, so I believe that she can certainly tell the differences in scent and heat signatures of humans. (I've seen mention in some threads of owners putting pieces of clothing that had been worn in with snakes to successfully acclimate to their scent, as well.)

Since I worked with animals for years and couldn't resist seeing if she would respond to behavioral cues, I started very, VERY lightly tapping the rim of Millie's tank 2 or 3 times with my fingernail whenever she would decide to climb up her branch to come out to visit. Since then if she has a day when she hesitates, if I tap she'll sometimes start climbing up. (Yes, I am trying to train my snake to come when called using specific vibrations, something I hadn't planed to admit on this forum!)

If you are looking for individual snake quirks to incorporate, my husband had another BP when he was in college that loved going to the movies. (He worked in a movie theater at the time.) He'd take her to preview night when the theater was basically empty, and she'd climb up to the top of his foot on top of the seat in front of him and "watch" the entire movie while periscoping off his shoe.

As far as realism in your portrayal of the BP, the thing that most struck me after getting one is how important it is to respect my snake's needs, if I want her to be her friendly self when she interacts with us. We make a point of leaving her alone the day after she eats so she can digest in peace, and don't mess with her for almost a week at a time when she's going through her shed. It's not like having a dog which is very much a pack animal and needs socialization and daily interaction.

If you post your writing online, I certainly hope that you post a link to it here, since I'm sure many of us would love to read it. Good luck!