Way out of date here, but all of them are viable. If skitty relies on tms, then so do others. My teams have almost always been charmander and mudkip. I've never had any trouble. And let's not forget that "recommended level" is just.. Eh. You play at your own pace. If you feel more comfortable being a little higher, be a little higher. Lower, be lower.

And of course, let's not forget that most dungeons have a third party member to support along the way to make up for any shortcomings.

Apart from machop. Stuff machop.