Very interesting, but I don't think it would be useful for 106% (assuming if it only works for the Nightmare Grimmkins), as 2 of the 3 you get are directly tied to the route (Brumm and Hive Grimmkin), and it definitely wouldn't be optimal to die to the Grimmkin in the Hive to skip the one on the way to Ancient Basin. Neither in 112%, because you don't get the Nightmare Grimmkins, but only abandon the Grimm Troupe.

BTW there's is a guide by fireb0rn for a load time remover in LiveSplit, which you can find in "Guides" :)

This route is already really close to the 4 Mask Shards category, where the only offset is rescuing a grub on the way to mawlek, so I don't see this becoming a category extension.

Timer starts on first movement and ends upon getting stuck, as in no way out, except cheating or using commands. Unofficial WR:

So do you mean there should be a category for each idol stage separately? Cause I think that it would be a good idea to have all 3 in one category, as I'm pretty sure that you have to beat the bosses in ascended before you can do radiant, so that would make it complicated to do a radiant only category.