Good luck convincing anyone this. The game has turned into a "choose your own head canon" adventure and the moment you propose theories is the moment you get shot down for them.

That said, I do believe Vemom is the GZ Medic. I don't know what's the deal with our avatar though and who could he be. Soldier 25 had a combat unform so it could be our avatar. Delta man too but that might be a tiny bit of a stretch, plausible but a bit of a stretch. You can think of it that BB got so traumatized by seeing us, the avatar (soldier 25), dead in his arms that when his memories got transplanted to us as the GZ Medic, Venom traded his identity to the man who literally died as us and us as the man that metaphorically died. I mean number 25 is seen in our damn ACC in GZ staring back at us and at BB on the other side of the bench. All while BB looks like he's in despair with the scars and burns we never got to see in that cut camp omega scene.

If you think about it, it does make sense. That said if we ever get a camp omega revisit, I want to know the deal behind the soldier numbered 25 and the delta guy. They're way out of place in this entire game.