For me, all of those models would be WAY more than enough for a live aboard for one person. One thing you need to look at is the ease of going out alone. Do you have easy access to handle lines from the helm, etc... that kind of thing.
As far as living on board, everyone has different needs and expectations. I know people that have lived, and cruised, aboard 30' sailboats and find it a perfect fit, others need a 50 plus foot power boat.
Much of it has to do with what your use to on land life. Big house, 2 car garage, big yard with a pool, etc.... The only way to duplicate that on the water is get a really really big boat
Are you keeping a land base, or are you chucking it all for the live aboard life style? We chose to chuck it all and embrace the live aboard life style head on. Sold or gave away everything, and I mean everything, when we moved onto a 46 footer. No fine china, no massive media room, no furniture, you get the idea. The stress of land life went away when all of those "things" that we had acquired over the years were gone. Removing the excess baggage from our life allowed us to breath.
Some have a hard time doing what we did, it was right for us but may not be for you.