My understanding is that when I capture footage via Cineform from my Sony V1U and Canon HV20, it removes the pulldown (if I check that box obviously). When I render via Vegas then to a DVD, I want the DVDA template that won't require re-rendering. The DVDA template for widescreen, 24p has the default to remove "2-3 pulldown." If I change it to NOT remove the pulldown (as I've already done it), I think it re-renders again in DVDA. If I leave it, what happens... does it try to remove 2-3 pulldown again?

DVD always has pulldown as there is no 24p profile. When 24p is added to a NTSC DVD, the pulldown is added back with the correct repeat flags so progressive DVD players work well. I don't know whether that control is to add the repeat flags and therefore should be on, or for detect 24p from 60i sources and therefore should be off.