Mira was "chosen"
by whom?
for what? it was HER choice: she loves books and culture; she doesn't want to be a peasant's housewife, therefore becoming Athia's priestess was her
only doable choice.
Isha being behind the incident during Mira's initiation is
your assumption. We don't know, but my educated guess is that another deity is behind it.
I think you
don't understand the meaning of Love and Corrupt points in this game at all. What do you mean by "without romance or corrupting"?

You're fighting with her, therefore you did her quest and you must have quite a few Lyvia Love & Corrupt points:
you are romancing and/or corrupting her.
Anyway, can we move on, now?