Soontir PTL, Hull+ Stealth

Rexlar-Predator

2 Academies

I ran a similar list using Vader with EU+Outmaneuver instead of Soontir and had fun, those academies really do a lot of damage just plucking away at range one while your opponent focuses on your "real threats"

Darth Vader with swarm tactics and concussion missle

bounty hunter with Heavy Laser Cannon

Obsidian Squadron (tie)

Academy (tie)

I don't have many 4 ship imperial list, but there is one that I am constantly refining and which is getting close to its final stage:

Name: Vader's Meta

Vader

Concussion missile

squad leader

Sigma squadron pilot (phantom)

Rebel captive

Stygium particle accelerator

Scimatar squadron pilot (bomber)

Proximity mines

Backstabber

Backstabber and the phanom move in opposite flanking, with the bomber covering the center and Vader following where he's most needed. His squad leader ability is intended to be used to maximum effect, from recloaking the phantom if a mistake was made to offering late turn barrel rolls and, if the opportunity presents itself, remotely activating the proximity mines. It's a concept where you have a pilot with 9 PS rating where you can do equally welll whether you have the initiative or not.

Onyx Squadron Pilot (32)

Always take Delta over Onyx. Near unblockable K-turn is much more useful than a tiny PS boost, and it saves you two points.

What about predator?

May or may not come up, that ship still gets a reroll anyway, and it's still not worth it. If Onyx were PS4 or PS5 then maybe there'd be a case for it being at least on par with Delta for quality but all things considered in my book it's worse.

If you want a high PS defender find the points for Vessery or Brath, otherwise you're far better off taking Delta and leaving Onyx and it's ghastly "art" to gather dust with Storm Squadron Pilot and Fel's Wrath.

Unfortunately I didn't see a phantom in your Sig, because I made up a themed squad today that may not be good but would be tons of fun. I call it "Hooked on Phonetics"

Echo with ACD

Delta sq pilot

Alpha sq pilot

Alpha sq pilot

It has PS and hp issues but I think it could be fun.