In regards to Au Ra lore and naming conventions..

[Balipu]

X comes before Y.. so Yae is already there. as for Nero.. we know his Rank. his is Tol. http://finalfantasy.wikia.com/wiki/Nero_tol_Scaeva

Yes, we know that his rank is Tol. We know everyone's rank. What we don't know is, what those ranks actually are.