EDIT: Just looking over their character bios, Stass Allie is actually super convenient, because they look almost identical (at least they would when downgraded from real life to TCW style) and Stass Allie doesn’t appear in TCW, so in my version, fine, she does. Replacing background Adi with background Stass doesn’t break canon at all outside of TCW, so that works nicely.
Sure, that could do it! It’s to be noted that Adi still has a fair share of close-up shots, speaking parts and mentions by name in some episodes, like the Citadel, where deleting her lines would affect the overall dialogues. Maybe you could increase the pitch of her voice to establish her as a different character (Stass Allie)?