Since I finished this TAS, a bunch of new glitches were found that have led to about 20 minutes of timesave. Here is a doc with all of the new findings:
https://docs.google.com/document/d/1oOEv4GPXC4qZ7lzriDkyvL1q6QcV4ub98rV-F_xiMME/edit?usp=sharing
I expect more glitches/skips to be found, so I will wait to begin a new TAS because I don't want to start over if a skip is found halfway through TASing. Also, the game needs to be rerouted, notably since I'm pretty sure the US version is faster due to exclusive glitches, even with increased boss health.
There is one US-exclusive glitch that is not understood well. If Mario is standing still on ground that is below the ground Luigi is on, Luigi will try to walk to Mario, but can't reach him since their heights are different. When Luigi reaches Mario's X and Z positions, on non-US versions, Luigi just stops, but on US, Luigi teleports somewhere. If he teleports to a close location, he will continue trying to go to Mario, resulting in another teleport once he reaches Mario's position. If he teleports far enough away, he will stop moving. In some cases, Mario can then teleport to Luigi after Mario starts moving again. This is useful if Luigi teleports out of bounds, because he can bring Mario out of bounds with him. This is used for a sequence break in Gritzy Caves. However, we have no way of manipulating where Luigi teleports to. If anyone is looking for a glitch to experiment with and figure out, I'd love your help.
Also, here's an invite to the series discord server:
https://discord.gg/2AfNrh9