a) Because David, like the majority of other OVW/HWA/developmental talent, wasn't up for the draft. (Lesnar, Mark Henry, and Rico are presumably being bumped up to the big leagues, but they're exceptions.)
b) Dunno. I think that'd be a pretty amusing angle, but then I'm a Test mark. Of course, just because Test shows up at Raw doesn't mean Flair has to book him, or even let him in the building, but he could always do a run-in. Maybe Vince will send him over to get the Hardcore title back from Raven.
You (surprise, surprise!) are missing the point. Parody is one thing. Impersonation and trademark infringement are another. You can't just do whatever you want and yell out "Parody!" whenever someone doesn't like it.