BTW folks are in IRC (#openacs), you should join us (though I'll be taking off for a couple hours soon).
Anyway, our consensus is that you needn't bother with upgrade scripts. Let's just make the fresh installs pass the AA tests. Constraint naming errors don't really break anything, just make it harder to find which constraint died if you don't use unique names, and without a standard naming convention people tend to duplicate names.
So if you want to take on the last two items you've listed, that's sufficient.
And will be greatly appreciated!