Probably not since the Cascade 2D sections don't have horizontal opening. Also, since you'd need to replace the Madame Broode multimoon, it probably wouldn't even save time.

Overworld doesn't want it added just yet as you've said, it's still in demo.

I believe playing off of an online emulator and submitting runs like that is allowed, but I'm not 100% sure.  It's up to the mods to decide.

that's not hte discord for speedrunning though

https://discord.gg/HKVxdSu

Here's the proper link

Super Mario Bros.

Roblox

Super Mario Odyssey

Robot 64

2D Fly Glitch To Skip Madam Broodal?

emulator website?

Robot 64 Discord Server

Robot 64 Leaderboard/Speedruns

Otterstone_Gamer

Minecraft: Java Edition

Celeste

Bygg bilar med Mulle Meck

Marble It Up!

Minecraft: Java Edition Category Extensions

Turnip Boy Commits Tax Evasion

LEGO Builder's Journey

Filtered Seed Glitchless

My Little Pony: A Maretime Bay Adventure

VilleOlof