Can someone guide me on what emulator is allowed for this game on the NES/SNES mini? Will the default emulator be accepted? I see that retroarch is forbidden.

Default emu is fine for runs. retroarch was only banned due to lag frame emulation being ON by default. Basically any "official" Nintendo release is generally fine and accepted for runs. Just saw this post, sry for the delayed response! :)

Thank you very much for the response.