Complicated though. From what I understand you have to be born an Omega you cannot grow/evolve into an Omega. Yet you may not display Omega levels of power initially. As an Omega however your powers have limitless potential to grow/evolve. So how can you tell which are Omega's but just haven't displayed those levels of power yet? 🤨
BTW Quentin Quire also underwent a secondary mutation I think due to "kick" but I don't think/can't remember if that triggered his Omega-ness and also btw Elixir isn't infallible I recall him not being able to heal Northstar for some reason.