It's so cool to have Agate explaining backstory from Trails in the Sky to Class VII. I do wonder who the other A-rank Bracer is who came to Erebonia with him. My first guess would be Schera since we already know it can't be Estelle or Joshua. It couldn't be Cassius since he's not a Bracer anymore (Plus, I'm pretty sure he achieved S rank or something anyway).
I'm with you on first guess being Schera. Cassius is indeed S-Rank (although during FC it's stated that S-Rank is a "secret" rank so I don't think that's supposed to be public knowledge that it even exists) and not a bracer. Kurt is the dark horse option. He was A-rank, and I want to say at the time of FC/SC he was actually the only A-rank in Liberl. Agate and Schera were B-rank back then though Agate at least was obviously promoted. Anelace is probably out, SC makes it sound like she was also a newb with Estelle and only had a few months on her at best. If saving Liberl from Ouroboros and the Liber-Ark couldn't get Estelle and Joshua to A-rank (they were robbed) there's almost no way Anelace got there having not even been on that op (also robbed.) Guess there's the rest of Kurt's crew but I don't think we know their ranks.
I actually thought of Zin too before remembering he's from Calvard and shouldn't count for that discussion. ---
xp1337: Don't you wish there was a spell-checker that told you when you a word out?