Having 4 of your 5 choices here currently, I'll offer these comments:
-personally, I'd choose the ball or BRB, probably the BRB
-even the 3' tank isn't really a great size for an adult ball, and especially for an adult BRB. I think 4'Lx1.5' W is about the minimum footprint; height is largely irrelevant for both species. So plan to get a bigger tank within a few years if you choose one of these two.
-CB kingsnakes and milksnakes that are handled regularly will generally be relatively calm, and musking isn't too common
When will you be at the Totally Pets Show? We'll have a booth there but I will only be there on Sat. after 3.