1) when Xehanort gets hit by the laser is good.
2) I think having lvl1 for each difficulty is fine, with that said, as it is right now, I agree with proud lvl1 not being a good idea for a speedrun category. Hopefully this will change with later updates.
3) In my honest opinion, pre-order stuff shouldn't be part of a speedrunning, the reason being that not everyone has the opportunity to use it, This is different from other dlcs that are not related to pre-ordering, since anyone at any point can get those dlcs.
4) Well, at this point all worlds would be classified as the meme category, kinda hoping for an actual world with a later dlc for that kind of category. Also, while it is technically a world, it is not a world you can travel to like the others with the gummi ship so it's a bit weird but i digress
5) I've always thought that if the IGT is good it should always be used to avoid all kinds of weird stuff with the load times.On a personal note, this was a big issue in Nioh, where the IGT counted the loads and it didn't even count the seconds, in this game it looks good though so I would recommend using it.
I haven't done a run of this game yet but I do plan on at some point.