Darth Maul vs. Qui-Gon Jinn & Luminara Unduli

Maul as of Son of Dathomir.

Jinn as of The Phantom Menace.
Unduli as of Revenge of the Sith.

Maul has his darksaber and red-bladed saber. Battle takes place on the Naboo plains.

I'd say duo. They're both pretty darned impressive master duelists... though Maul's force powers are a threat.

Maul in a good fight.

He became more powerful, and while we haven't seen him use Jar Kai to my knowledge he's more than capable of removing Jinn with the force and killing Luminara

Not sure, tbh.