I don't know the answer to #3 but I know PAL is allowed, not sure what the conversion is for it, I don't know how many people check the threads on this site, I would also ask this question in the discord, you might get a quicker response

but for #1 no restrictions on being within X time, if you get a PB feel free to submit them!

for #2 so long as you have a video from start to end I think you should be good, splits are nice but not necessary