Salamanders are not harmless. Their funny homing ability causes curving paths confuse frigates which try to rotate to face them and often hit frigates before they can be destroyed. Which just leaves frigates vulnerable as most of their ability to survive is in their movement. The more salamanders you have, the better, and they can be fitted on any small or medium mounts. Anything that gets hit by them and get their engines disabled usually die shortly after as they can't manoeuvre. Even if the engines aren't hit, it can also disable weapons. Salmanders often rather suprisingly are able to avoid getting destroyed by vulcan cannons and machine guns due to the homing ability.
Anyways I've found Tempests and Omens to be good ships to assign them to escort with, but that probably because the Tempest kill every other frigate and is survivable and the Omen kills every missile and fighter near it. Both are fast. Other than that I haven't really done much testing with escort.