Thanks, Nikko!
The GENIO was the hardest of these to find - mine's the only one I've ever seen for Constantine.
It's more common for Maximianus, although I don't have one.
The precise dating of these fractions is interesting. It seems that, roughly, Maximianus's title on the coins is changed from DN back to IMP at the same time that Constantine is elevated from caesar to augustus, but apparently these title changes didn't happen at the *exact* same time since we have these fractions with IMP MAX but C1 CAES. There is also a single unlisted specimen with DN MAX on Not IN RIC.