It would be really hard to go wrong with any of these bikes; Rans, Bacchetta, Volae. I have heard more comments about the dual 26 bikes being a problem for stop and go traffic than the 26 x 20s. On the other hand, the 20" front wheel won't negotiate rough terrain as well as a 26. Trail riding is possible with either style using wide tires, but you did say you like the option of thin tires.

Another thought is to go with a used bike to minimize cost until you have some experience. One bike is never enough anyway.