I'm going through a mental health MEB as well but for a personality disorder and, while I don't have experience with being found fit, I do remember extensive conversations regarding a very real possibility that I could be. You're already doing all the things that they told me to do (i.e, second opinions, letters from leadership/friends/co-workers/etc.) if I were to try and fight to be found fit for duty. However, that conversation was short-lived as I found myself in the hospital for a week for SI/mania not long after, which meant I had to be on certain medications that weren't allowed for continued service in order to cope with my disorder. At that point, I ruined any chance I had for arguing to be fit for duty.
To my understanding, if you ask for retention in your Commander Impact Statement (CIS) and they agree, your leadership/peers agree, your provider agrees, and you have no behavioral issues at your work center, then you could have a good chance of being retained. Of course AFPC can either agree or disagree with their statements for your retention once your package gets to them, but regardless of their decision you have the right to seek legal counsel and appeal it.
Just remember to be honest with yourself and your providers during this time. Do not sacrifice your well-being and mental health for the sake of staying in.
