Are emulators allowed for runs of this game? If so is there any noticeable difference between the emulator and actual ps2 for this game?

I haven't done extensive research into emulation for this game. However, from what experience I have dabbling with it so far I saw it lag in different places than the PS2, i.e. places where the PS2 lags will play smoothly in emulation and vice versa. At the moment I see no reason to disallow emulators. Submit your run(s) and just make sure that you include which emu you're running the game on in the run description.