Hey, sorry to hear about facing an FEB. It truly is a sucky experience.
I went through one in 2017 and it was a similar situation to you, I washed from a FTU. Here are a couple pieces of advice I would give you:
1) Work your network to get people to vouch for you. See what your current leadership and instructors are likely to recommend. Reach out to UPT IP's and see if any will write you letters of support or testify for you. I ended up having two of my UPT IPs come voluntarily TDY and testify in front of the board and vouch for the fact that I was a competent and capable pilot.
2) Be wary of the legal advice your ADC gives you. Ultimately this is your aviation career at stake. In my case the ADC recommended I NOT fight to get reinstated into my FTU course, as he thought it may burn bridges and piss people off in the training squadron (the FTU planned to recommend my removal from the course but reassignment to a new airframe). I went with his recommendation, but ultimately in the end I think that was a mistake (see conclusion below).
3) Keep a record of everything that occurred leading up to and during your FEB. You never know what things you might catch or discover that could help your case now or in the future.
4) Keep your head up! Show up every day with a smile on your face and do whatever job they stash you in with the best attitude you can. Be a bro. Even if this ultimately doesn't help your case in the end, it will help your personal sanity. Also own the fact that you are facing an FEB. Don't be the guy that makes excuses about why you're in this position. Own the mistake and show everyone that you know you can be better.
Conclusion: Now here is the part you probably won't want to hear. You can do everything right in the process and still end up with a bad result. The FEB is set up so that no matter what is recommended by the FEB or Convening Authority, the MAJCOM Commander has the final say. In my case I had the FTU leadership and instructors, my UPT instructors, and the Convening Authority all recommend my reassignment to another airframe/mission. And while I did struggle in my FTU, I had no history of failures in UPT. However the MAJCOM commander still reversed their recommendation and removed me from flying status. As mentioned above, if there is one thing I would have done different (other than change my study habits sooner and not even face an FEB), it would have been fight to get put back into my FTU. And as I mentioned above, I think saying that you just want to go to another airframe has to the potential to cause a bad perception. From the Convening Authority on to MAJCOM, your case will only be seen on paper, and whether right or wrong, it could be perceived that just wanting to move on somewhere else demonstrates a lack of commitment or seeking an easier path. Who knows if that really would have changed the result, but it could have helped for sure.
Sorry for the long post, but I know I would have liked to have read something like this back when I was in your shoes. If you have any other questions feel free to PM me. I have basically memorized the 11-402.
Oh one more thing. If you are truly passionate about aviation and can afford it, keep flying on your own. It could help your case. I've since been reassigned to a new career field, but I'm working on my CFI on my own, hoping at least I can get into civilian aviation, or maybe someday find myself back in an Air Force cockpit.