No squadron has both counter and escort currently.

Currently on X-Wings and TIE Advanced have escort. Which is good as if you have too many types with it, it would become useless (it only works on squadrons without Escort). Escort + Counter would be a bit OP I think, plus the way they have done the fighters means that each type has a distinct role (X-Wings escort bombers, A-Wings intercept enemy squads, etc).