All studios are 4 + infant, whether booked through
DVC or Disney.
This is my understanding of the 1 BR rules:
1 BRs are all unofficially 5 (+infant I assume) when booked through Member Services, but officially stated occupancy is 4+infant except for the places that now have the sleeper chair.
1 BRs are 4+infant booked through Disney if it doesn't have the sleeper chair, and based on a post I saw today, apparently at least OKW is still 4+infant because you can't book 5 in an OKW 1 BR on the website through Disney (someone posted this question today on the resort board). Not sure about AKV and BLT - I think you can book 5 in those through Disney.