1. Like that is going to work. The problem with that strategy is that Grievous' infrastructure is galaxy-wide. And any attempt to attack that infrastructure will be met with stiff resistance. Grievous can simply move his superior numbers around Revan's forces and hit him from all sides. Revan's only option is to spread his forces out to prevent that, but that means that his fringe forces will be targetted and eliminated.
I imagine Greivous will come across as the seemingly the most powerful, so I imagine this Kaggath will begin with Revan and G0-T0 (not teaming up) focusing on bringing down Greivous.
Revan will quickly learn that fighting the droid army head on isn't tactically the best course of action. But there are several ways to beat Greivous.
1. Scorched-earth tactics. Revan can send an enemy force around the enemy and attack their infrastructer like Sherman of the American Civil War. He could accomplish this by goading Greivous into a fight. Greivous will avert his attention and resources to a point that Revan has purposefully weakened. As this happens, Revan will send an army around to, like I said, wreck Greivous's infrastructure.
2. Assassins. They will be extremely decisive in this Kaggath. A group of assassins (with or without Revan) could beat Greivous.
NOTE: some might argue that these assassins won't be very effective. I disagree. Look at what Asajj Ventress and 2 Nightsisters almost did to Count Dooku in TCW.
2. Grievous has a company of Magnaguards with him, not to mention cruisers filled with Battle droids. And don't bring the assassins into this. They are just normal men (the non-Force user ones) compared to Grievous. They can't use their 'drain' ability on him as he has no strength in The Force.
Ventress is an incredibly skilled warrior and the Nightsisters are completely different from Revan's assassins. Not to mention that Grievous is incredibly difficult to kill (either straight up or from him running away).