Also lets not forget Kristoff and Cassie were in an AU together as well, I really love the pairing.

I think that the reason no one knows what to do with Kristoff is that he humanizes Victor which they don't currently want. As seen by the last few years of writing they have been pulling Doom back from that almost an anti hero arc to full on villainy with slotts version in FF. This might be due to them resetting the status quo for FF so they can intro them into the MCU.