As Chucky and others have said, bike fit and also your preferred gearing matters far more than how compact the fold is and whether it rolls nicely once you have folded it. For a newbie, the fold might seem to be everything, but after you ride it for a while, how the bike handles on the road is far more important than the size of the fold. Once logged enough miles to think about changing bits and pieces on the bike to suit your riding needs, the availability of parts and ability to change parts become important.

Once I fold my Dahon (it has a rear rack), I tend to carry and lift it with both hands up and down stairs. Any of these bikes will fit on a train next to your feet. All of them will fit under a desk or in the trunk of a reasonably sized car. I think the Dahon Curve (16" wheels) would be a good bike for your needs.