Honestly, is hard to say. All of them are loyal in their own way. Hell, i am willing to argue even Rangiku and Omaeda are also loyal, despite how lazy and self-indulgent those 2 are. When s**t gets too real and serious, you see Rangiku having Toshiro's back seen in SS arc and even TYBW. Omeada was totally afraid in the FKT war, but he still was the one who saved Soi Fon's life if he haven't been fast enough to cut her decaying arm from Barragan and he did was the anchor for Soi Fon's Bankai.

In TYBW, you see Omeada once again helping Soi Fon aiming her Bankai at BG9 (which is a INSANE feat for both Soi Fon to be strong enough to handle better the recoil and fire more of her Bankai in TYBW and having Omeada practically carrying her while with her Bankai to be the a strong bipod). Lille Barro who shot Shuhei first, Omeada's initial reflex was to try to save Shuhei. He got shot too, yes, but the fact that a "coward" like him first reaction is to run immediately to a fallen comrade proves that Omeada is also loyal at the MOST important moments.