You seriously can not compare what Hit Girl and Big Daddy's abilities are to Obi Wan. That is just lunacy. The Fetts would kill them both. Probably quite easily as well. As for your argument about the armor. Man Boba Fett appeared in an old ass movie where that shit he had on worked for what was going in on the movie. If Star Wars were made in the time where Kick Ass was the Mando armor would of been how it was intended to be.
Also I don't believe giving examples of Boba Fett falling into the pit is a good example either. Once again Luke Skywalker >>>> HG and BD. (not to mention Fett lived)
As for actual combat prowess. The Fetts once again win. Considering BD wasnt alive for the Jetpack he doesn't get to use it, and HG sure as shit isn't using it either. That takes that out. Jango's assassination with the Kimino dart proved how accurate and fast he can kill. Not to mention they do have blasters, rocket launchers, flame throwers, ect ect. I think you're also forgetting they have tracking droids, and systems. Not to mention Slave I alone would be enough to wreck their shit. The only thing the Fetts would probably fail at is bringing them in alive since BG and HG don't roll like that.