Zoned as 2 units, has an attic separate studio

[Brendan L.]

I'm looking a property that is zoned as 2 units, but has an attic studio with separate water/heat. My goal would be to live in the studio and rent the 2 units below. Would I run into any issues, legal or otherwise, by doing this? Would I benefit from having it rezoned to 3? If I want to eventually move out and rent the studio, must I have it rezoned to rent that out? Thanks!