the answer to the Ackbar question is that his B-Wing had been sabotage and he crashed it into the Cathedral of Winds on Vortex. he didn't want to face the shame and therefore retired to help study the ocean bed on Mon Calamari. (he didn't know it was sabotage.) he then came out of retirement to command a ship with Leia Organa Solo at the Battle of Anoth. to save Anakin Solo before an Evil Caridan guy (forget his name) could take. him the name of the Saboteur is Tarfen, and it wasn't his fault the Caridan guy had control of his brain.