IANA application is applicable iff draft is about to go RFC; I'm not related to that author in any shape or form, so no clue (not even sure if draft is going anywhere, in IETF86 there was muted response at best to it if I remember right).
What about the non-prefix colouring work, like source-based routing, prefix allocation, basic DHCPv6 fixes, etc.? Could that be merged upstream?
For the prefix-colouring work, you could always commit the code using a vendor option and then update it when/if the draft gets traction?