Normally I agree with the outcome of Vs. videos but in this case I'm going to make an exception and say Barriss and Luminara take this.
Even with two lightsabres Kenobi won't be able to win. The video I suspect inspired this thread claimed Kenobi's win against Maul & Savage was "proof" he could beat Barriss and Luminara but I disagree. For one thing their teamwork and synchronicity is far better than that of the brothers and secondly Kenobi was able to beat the brothers in part because the confined environment worked to his favour as it meant they kept getting in each others way. In an open field where Barriss and Luminara have plenty of room to maneuver that won't be a problem.
I'm sure Kenobi will last a good while due to his ace defence but eventually they'll manage to beat him. I believe that a pair of well-synchronized fighters, both of whom are Form III experts in their own right are among the few who could overcome his defence.