[Jack Simth]

Almost right.

Missing two players, you would normally subtract 2 from the CR of critters you throw at the party and expect to do "normal" stuff. So if the appropriet challenge for a party of four would call for a single CR 6 critter, you instead need a CR 4 critter.

With gestalt, you throw things that are CR +1 if they don't particularly rely on abilities with saves, CR +2 if they do. If the appropriet challeng for a party of four would call for a single CR 4 "fighter" critter (no "save or" effects), you use a CR 5 "fighter" critter instead. If the appropriate challenge for four would be a single CR 4 "mage" critter (lots of "save or" effects), you use a single CR 6 "mage" critter instead.

Merging the two, it's CR -1 for things that don't particularly rely on abilities with saves, CR for things that do.

Violist:
Idea: We both put Druid on one side, for the animal companion to round out the combat ability of the party. An Ape makes a half-fighter (especially when Trained for War (the Combat Riding general purpose will do that job, right?) for the armor profincy and put in, say, Leather Barding (40 gp) with the Druid Bonus Trick going for the upgraded attack). Put an "exotic pack saddle" (15 gp; could also take an Exotic Military Saddle and Exotic Saddlebags for 64 gp) on the apes, have them carry stuff, dump our characters' strength, and have one of us take the "rogue" half and the other take the "wizard" half (split the healing/buffing). As a bonus, we end up with a "themed" party. Sound like a plan?