I think the Elementalist is salvageable - it's balanced at 6, a bit too good at 3, and way too good at 1. If you push the companion sizes to small at 3 and medium at 6, it would be fine, although the small companion might be a bit too squishy for a melee combatant. Maybe bring the shifting into elemental form forward to 3, move the resistance to 1, and give a familiar/homunculus level mini-elemental at 1.

The Demonologist would be more interesting/fluffy with Lesser Planar Ally or Binding as the capstone SLA, although I don't know how balanced those would be.

The Vindicator's middle ability is worth keeping, if it can be worked into a new/replacement archetype.

The Paladin's Lay On Hands is pretty weak, and the Cenobite should probably get something better. I'm not sure exactly how I'd scale it, but it should have some sort of base healing so that a Cenobite with 10 to 15 wisdom gets some real use out of it. As it stands, it'll heal less than a hit worth of damage per day at low levels, so it's really only useful for stabilizing allies.

The damage for the Cenobite's medium archetype power should probably scale a bit. Maybe wisdom mod + (1 per two levels).

Faster Than The Naked Eye doesn't do anything for Brawlers when they get it, unless they're dual-wielding. I'd change it to something like "The Brawler may make a full attack as a standard action or part of a charge or make two attacks, one of which has a -5 penalty to the attack roll".

The thief-acrobat's greater ability doesn't really do anything - with full ranks in tumble, even without a dex bonus or any attempt at optimization, he gets 25 by taking 10, enough to move at full speed through one opponent's threatened area. With a +2 dex bonus and the synergy bonus from jump, he can go past 3 enemies without having to roll.