This is quite possibly a stupid question:

Going by RAW it would seem to work just fine, but also seems a little over-powerful, so I wanted to make sure (side effect of being fairly new to armada).

Howlrunner's ability to add one blue dice to another friendly squadrons attack; does that still work when the squadron is performing a counter attack?

And as a corollary question (with probably the same answer) does the swarm ability work on counter attacks too?

Just casing viability for a dengar/howlrunner fighter ball

Yes.

Counter Attacks are, for all purposes, attacks .

Things that apply to attacks, apply to Counter Attacks as applicable.

It's called a tie interceptor in range of dengar and howlrunner countering with 4 blue die....

32 minutes ago, slasher956 said:

It's called a tie interceptor in range of dengar and howlrunner countering with 4 blue die....

Add Instructor Goran...

...and Stronghold

9 hours ago, Green Knight said:

Add Instructor Goran...

...and Stronghold

And a swarm reroll.

48 minutes ago, Mad Cat said:

And a swarm reroll.

And Sloane.

And a ship, because a single fighter cannot fly this far out.

What was the question again?
Ahh, counter. Yes, what @Drasnighta said.

1 hour ago, Tokra said:

And a ship,

Stronghold is.

I ran that very Sloane/Goran/Dengar/Howlrunner combo last night. Threw Soontir into the squadron to make them jumpy, plus Vader in as a meat shield that would guarantee fighters begin to rot right away. It was magical. Every enemy fighter was dead by turn 3.