I honestly don't play Rebels ever, but upon purchasing an Ewing to ease my OCD completionist side I realized that Etahn would be absolutely deadly in my local area in the escalation format. I have a tournament with some pretty excellent prize payouts coming up (Tantives, transports, etc.) and I really want to come up with a optimized anti-meta list.

So to begin here is the local meta for escalation as far as I can tell from seeing people playtest recently.
1) Swarms (they are pretty great in escalation)
2) Phantom (usually echo with some upgrades) and an interceptor (I think) @ 60
3) Elite Falcon builds with some small ship support
4) Bounty Hunters (didn't get a good look at the couple guys running these as they were only playing 60 points, but they both had Rebel Captives
5) Elite Xwing builds

So here is what I have come up with after reading some posts on these forums and a few blogs.

----------Imperial List----------

(Found this list in the Escalation Compendium thread and I can't really find anything to tweak)

60
Whisper - Recon Specialist, Sensor Jammer, Advaced Cloaking Device, Veteran Instincts
Academy Pilot
56/60

90
Whisper - Recon Specialist, Sensor Jammer, Advaced Cloaking Device, Veteran Instincts
Academy Pilot
Bounty Hunter
89/90

120
Whisper - Recon Specialist, Sensor Jammer, Advaced Cloaking Device, Veteran Instincts
Academy Pilot
Bounty Hunter - Ion Cannon, Tactician
Backstabber
110/120

150
Whisper - Recon Specialist, Sensor Jammer, Advaced Cloaking Device, Veteran Instincts
Academy Pilot
Bounty Hunter - Ion Cannon, Tactician
Backstabber
Bounty Hunter - Ion Cannon, Rebel Captive
149/150

The only thing I can see possibly changing is swapping out Backstabber for an Academy Pilot and 2 Seismic Charges to get a bit more control and some anti swarm, I really don't think that there is a right answer here, but it will come down to who my opponent is!

The idea is Whisper is a huge pain in the backside to kill. 60 points the Academy Pilot is the obvious target just to try to pin down Whisper. My only real hard counters here are those Bounty Hunters with Rebel Captives and perhaps a Han + Gunner build, but I think that Whisper should take out an elite falcon pretty easily if the dice gods don't decide otherwise. After this it is just a matter of making juicy targets that can take down Whisper's hard counters.

----------Rebel List----------
Build based on Etahn's ability

60
Blue Squadron Pilot - HLC
Blue Squadron Pilot - HLC
58/60

90
Blue Squadron Pilot - HLC
Blue Squadron Pilot - HLC
Etahn A'baht
90/90

120
Blue Squadron Pilot - HLC
Blue Squadron Pilot - HLC
Etahn A'baht
Kyle Katarn - Blaster Turret, Moldy Crow
118/120

150
Blue Squadron Pilot - HLC
Blue Squadron Pilot - HLC
Etahn A'baht
Kyle Katarn - Blaster Turret, Moldy Crow, Recon Specialist
Blue Squadron Pilot - HLC
150/150