Adi's performance against Savage/briefly matching blades with Grievous are better feats than any of the Inquisitors have shown. Though I'd question her efficacy against two opponents who are approaching her in skill (GI's technical mastery being greater, and The Seventh Sister having bested Kanan who defeated the Grand Inquisitor) in a moment of clarity in the force/held her own against Ahsoka Tano. Ahsoka is at least on par with Adi as of (Future of the Force), so even if the Seventh Sister loses to Adi, she has no feats to suggest she could best two duelists who could at least present a challenge/nor the force feats to suggest a victory via telekinesis.
I think the most debatable aspect of the fight is probably the Fifth brother, as he has shown very little combat ability in Season 2. He's physically stronger than either Jedi, but can probably be easily outmanuevered by them or thrown via BFR. While I don't think any of the Jedi have any feats to suggest they could beat the Inquisitors 2 vs. 1 (Yes they're better than fodder TCW magnaguards), he's a liability when hes's not using his telekinetic strength. The Jedi could win via the routes that I posted, but if he resorted to his TK than the Jedi would be more or less ****ed as he seems to be quite strong with showings like destroying a speeder with a lightsaber throw, ragdolling Kanan Jarrus, and telekinetically holding the ship Ezra was in with the Seventh Sister.
All and all its a debatable fight, with either 2 Inquisitors being capable of killing any Single Jedi but with the Fifth brother being killed by either Adi or Eeth.
EDIT:
Kenobi is more powerful than any of them, and unless two of them can use telekinesis to hold him in place they lost for a majority. They aren't beating him in a duel either