Abaddons mouth with henchies?

Possible? If so which henchmen should i take? and any advice on what skills I should have equiped? (Ranger/mesmer)

Yes.
Both warriors, both monks, Cynn, Eve, Dunham.
However this mission will be much easier if you can use rebirth.

Your best option is to play an interrupt ranger (especially if you are forced to kill the monk boss), and to equip a sprint-like stance + rebirth. If things get ugly, run away, resurrect, and try again. Take small bites, target softies first and bosses only when everything is dead. Take your time for seals and don't forget to kill all guardians before breaking another seal. As long as you're alive, this standard 'hit and run' strategy can get you through most missions, even if some of your henchmen hit 60% DP.

yes it is possible, even with the bonus, in a full henches party. i did both with my mesmer and henches so i'll just describe how i've done that.
u can take the henches u like as long as the 2 monks are in the group.
set u up af domination mesmer. reccomended skills are power block + backfire emphaty and chaos storm.
its not hard, u just need to be careful not to lure more than a group of foes per time: kill the jades on walls before u enter the fort. then enter killing one group per time. jades groups are pretty easy to kill, just spam emphaty on them and chaos storm if henches are running out of health.
As for jades groups, first thing is to backfire the elemenlist to them him down soon, once their main dmg dealer is down u can kill the rest easily.
the only really hard part in this mission with henches is to kill the first 2 bosses, usualy the ranger jade and murssat monk. u need to lure away from the circle and try to box the monk, stuck him. cast power block on him when he's using any healing skill and he wont be able to heal for 15-16 seconds. if u want to be safe u can bring archane eco with u too and have 2 power blocks on him to disable his protection players too.
once monk boss is done, mission is a mere run. just kill anyone with ease using backfire on casters.
That's at least what how i've done the mission.
if u wanna do bonus too... easy, just take your time to clean the full way till Leah Stone's Tree, then get back, rescue and follow him slowly to complete bonus

I did with a pure henchie party on my mesmer, easiest way to kill the monk boss is the manuver the henchmen to surround it. Then it can't flee from any AoE's that just happen to fall on it's head

I tried with hench also... just couldn't get them not to aggro the whole lot at the first bosses you guys have been describing. And since I am a Mesmer/Elementalist... no rebirth.

But I do believe it is completely possible with hench.

Yes, it's possible. I did it with my R/N, and I didn't have any problems. Take it slow, don't rush. The only issue was at the end when I had to interrupt the monk boss's Orison of Healing with Distracting shot

As long as you are playing an interrupter you can get by with them.

With my warrior and Disrupting Chop I couldnt get past the second boss group. I love those henches but they just a little fell short on this mission.

When getting the elites from the dryders, I found as long as I had Drain Enchantment in case of a certain monk Mursaat there was nothing I couldn't stop.