Some short question: is PC emulator allowed? Will it be qualified if I play on emulator? If sm64 not, can rom hacks be done on emulator?

Yes - There is a leaderboard for it (It just doesn't automatically show when you head to the SM64 page on speedrun.com)

If i recall correctly there is a drop down for what system your using. Something like
^platforms & emulators
^platform only
^Emulator only

Thanks for replies!!