On my side, being a fire-starter chooser, I'd pick all of them if possible. Since that's not the case though, Charmender would be my first choice, just because it evolves into badass Charizard. Next in line is Torchic, mainly for the same reason as charmender. The only one I'd have some regrets would be Fennekin: not only its final evolution doesn't have a particularly good design, Delphox's moveset is extremely shallow (big lack of coverage, especially counting Focus Blast, that almost every other Psychic-type pokemon learns)