I never received the drops for the HCS winter skins. I watched all the hours on twitch, linked accounts, and even waited almost a week for this to just solve it self. The odd thing is that I received the stance from that same watch time, but did not receive the other 3 rewards even though I claimed all 4 of the rewards on Twitch.
This includes a section on what to do if haven’t received them:
https://support.halowaypoint.com/hc/en-us/articles/4415570792724-How-to-claim-Halo-Infinite-Twitch-Drops