Update: While working on version 2 and waiting for some of the media to be delivered (hana's VA and a lot of stuff from Stoichion) I FINALLY figured out something to make Onyeka stand out and give her a bit more depth: I'm going all-in with the snake parts on the former naga. For a long while I was struggling and I was dissatisfied with her, since Kaliska has the female swordswoman, Hana had the femme fatale and battle skirt part and Leona had the fully-armored part. Worse, her character felt lacking, as the only thing she had going for her was a minor magus hatred and her wanting to return to her original body (which was obviously doomed from the start and any player could pretty much guess it since that would mean turning a waifu into a generic NPC monster).
Basically as it was, her whole character arc boiled down to accepting that she was human now and learning how to behave. Now, instead she will be some freakish midway from naga to human from the start, not just a different mind, complete with scaly skin, weird face structure etc., and as a result she will not be able to fit into either society (nagas or humans), being viewed as a monster from both. I think it will make for a much better story and give me a lot of freedom on what to do with her.
Edit: Will also be interesting to see if the berserker players will still be inclined to help her if she's the opposite of a smooth-skinned babe who just has some identity issues.