I'll answer what I can. I have 5 short tails, 2 of them are blood pythons. I haven't been bit by an adult but I imagine it would mainly be the force behind it that would hurt, their teeth aren't all that big. Most of the scary temperament stories come from wild caughts decades ago. They tend to be defensive and might nip as babies but you can barely feel those. They give plenty of warning, are easy to read and calm down well with age.
Body condition, they have a prominent spinal ridge and should be thicker in the middle, tapering off at either end. They don't need to be fed very often or large meals, my adults get a medium rat or equivalent about once a month. They shouldn't be round.
They like it enclosed, a tub or pvc cage is best and as hatchlings would prefer a small cage. They like to burrow so give them something to hide under. I don't add any clutter really, just hides and paper. Once they settle in you can move up pretty easily. I went from 18"x24" to 3'x2' to 4'x2' for mine. They do pee a lot so a substrate that is changed easily and you can tell they have gone on is important.