but fusing is locked behind beating Deepwood so that's impossible.

Ok this is true for almost every fusion in the game except for 5, the ones in cloud tops. For some reason we can do these fusions without getting the kinstone bag which is normally what locks being able to fuse, and kinstone bag is in town which only exits the Festival state once you beat DWS.

This is done in the NG+ Reverse Dungeon Order run, we start the run by beating DHC, then we do an ocarina boost to get OG in Veil falls, do a respawn exploit off a dig cave entrance and climb veil falls without having beaten graveyard. From there we do cloud tops normally and beat palace, then continue to beat all other dungeons.

Would the skip down from Mt. Crenel to reach Castor Wilds early still be possible without doing Cave of Flames first?

Yes very much so, the potential low% route would go to crenel just to get the grip ring and the wind crest outside the dungeon before doing crenel clip and then skipping the boots to rush the things in swamp. We can do crenel clip by preserving the hot spring water and then using that bottle to get invulnerability.

Also, could bootsless swamp ever be possible without the cape?

Yes, Toads proved it possible with part 1 and part 2.

god gamer

1. A category that in its entirety is identical to a segment of another category just shouldn't exist, it should be unique with its own route, unless what you are proposing is an IL.

2. This is not the section that will get people interested in the run, its by far the most tedious and boring section that everyone wishes didn't exist. People burn out and stop learning the run by sticking in this area for too long, so its best to encourage people to move past this and learn the more fun parts of the run instead.

3. Not every idea for a category needs a leaderboard, if you find this fun and enjoyable then you do you. I personally make up loads of different "categories", route them and do runs of them for fun, but there needs to be a critical mass of people asking for a category to exist before it gets added.

4. Kind of taking aspects of (2) and (3), but I guarantee you that no current runner wants to nor would do runs of this.

5. (Personal gripe) "%" at the end of category names thats not preceded by a numeral or implied numerical value is a stupid naming convention (and yes I know we already have categories with these names but that doesn't mean they are good names )

I speak on behalf of no one but myself, but I beleive that most of the runners would agree on the points above. If you would like to discuss more about the game and talk with new people who are also learning the run then join the discord, there are a bunch of new runners who picked it up recently and have good experience with picking up the speedrun for the first time