well, i can't help you with your main question. I can't do backflips, though i hope to remedy that soon. The reason that flips are not Parkour, is that they are not useful. Parkour is all about creating the most effective methods of travel available to the human body, and if you were running from a ninja riding atop a flying elephant, you wouldn't even think of doing a flip. You would just book like none other, which would be Parkour.
ps, i can only think of *one* situation where a frontflip could be parkour, but that is *one* situation, and it probably occurs in maybe two places on the globe.
nothing against flips. flip all you want, but just don't call it Parkour. I'm not trying to be mean, or authoritarian at all, i'm just hoping that by posting this, i'm helping you out.
Good luck on your backflips!
edit-they both posted as i was...i'll leave this up as i think it...elaborates a bit.