Emulators is allowed in any and 100%?

Yes, as long as its an accepted emulator with correct settings. Use Project 64 1.6/1.7, or Bishawk

RetroArch cores accepted or not? Thanks! )

I think RetroArch runs the same core as Bizhawk so it should be fine. Emulators are not optimal for speedrunning, especially for N64 games as they are not accurate for most of them. Duck Dodgers seems to work fine on bizhawk core, similar to console.