I agree with that, since iirc Orihime rejects past phenomena and Yhwach's Almighty sees the future and none of those worked. So it does seem to imply Mimihagi exists only in the present. However, the reason that got rejected in the past was that after Yhwach absorbed the Mimihagi he could affect himself in the future and he supposedly gets the abilities of those he absorbs. Since, if Yhwach gains all the abilities of those he absorbs then he wouldn't be able to see himself through the future. Idk if profiles get "possibly" for abilities, but I feel like at best the Mimihagi would get a possibly acausal (type 2).