Hi Tagneah
We always get issued the Leaky 1 STAR initially, but if we want they seem happy to amend it to the CG8 (ie visual) STAR.
As far as night visual approach requirements go, if we had to maintain 2100' till the circling area it would make things a bit interesting (although bear in mind it's via a base leg rather than straight in, so you actually get more than 5.28 track miles from entering the circling area to the threshold. I can't remember exactly how many track miles it works out at - lately BN seems to be on 01 every time I go there!).
You're correct about the distinction between being vectored versus descending to LSALT/MSA. The practical interpretation is that even though we're following a STAR track rather than a radar heading, effectively we're under vectors as far as altitude is concerned and are therefore OK to descend to the MVA of 1500'.
If you were unhappy with that interpretation (and I've never met anyone who was), I suppose you could always get Approach to give you a radar track of 275 from Koupa to within the circling area, instead of following the STAR track of 275 ... which would achieve exactly the same thing but would probably make ATC think you were a bit of a prat!