With EA fighter capabilites and the Octurions' lack of AF capabilities, this may not end so obviously. The Poseidon needs cover, and then should duck into an Asteroid field to prevent long-range Battle Laser fire. I wouldn't put any fighters in front of the Octurion at all, just take the sides and aft arrays. Two or more of 4-1, 4-2, 4-3 crits might do it for you.
A Sharlin, on the other hand, is White Death. All the AF capabilities of the Fusion Cannon makes this fight a lost cause. Because you won't knock out the Z'Takk in time, you won't win there, either.
The Dilgar War ships won't have a chance against the fighter stack, even with those billions of dice. At 54 damage and no interceptors, this a threshold you can get to. But, then again, the Dilgar War ships are pretty poor across the board.
And, finally, you just don't fly carriers against the Narn.