Thank you for answering the questions I wish you luck. For #3 if you wish to go down that route I think I'd be interesting if the Goddess initiates it to sort of "push the changeover along" if that makes any sense.
Viewing post in A time of change (New spell) comments
Apologies for that. But I would suggest say someone gets the spell put on them. They would then be able to transfer the spells properties to others through touch or more romantic/sexual action.
I know that could probably be a bit of a more long winded process and possibly not in line with the story you wish to tell. Just an idea/suggestion is all.