After re-reading your post I think now that my assumption that you
were trying to get more color extraction may not be correct. I think
now that you are asking if sterilizing the must will give better
tasting wine by eliminating wild yeasts.

> 1.) Do you really see a difference? I know wild yeasts can present off
> flavors, but I thought the commercial yeast strains kill off the wild yeast
> anyway (by raising the alcohol above what they can handle).

If you add your yeast right after crush the commercial yeast will
quickly out-compete wild yeasts. So, I don't think this is the reason
some people add SO2 at crush and then wait to add yeast in 24 hours.
There could be another reason, but I think they are trying to get
better color extraction and want to slow or stop the wild yeast by
adding SO2 (or by cooling).