That's what I'm hoping for, yeah. Hard to have it make sense, but I'm trying.
Isn't really that hard, honestly. The Dark Secret of Evelyn's is easy proof of that.
Thus a harem depends on situations. If the Princess is bagged as a wife, the entire group can easily relocate via a little mind control. Twist that gray matter a little and most of the girls could easily agree. Especially with the scene involving Evelyn and Callie... once you handle Callie's other problem. Primrose and Samara might pose more of an issue than others, but that is simply by her very nature. Nell would be rather easy as she already doesn't feel as though she 'fits in' with society.
And I suspect the Fey Queen could easily interpret the vision to mean she is to join the MC. Ya' know... makin' babies and all that. That whole 'seed of carnal lust' being the excuse. Hell, the hubby can be handed off to the Leanan Sidhe. Keep the two pump chump properly contained.
And without the Princess involved you could still accomplish the goal. Granted, you'd need to have some after situation in which the crew increased their size of dwelling. Easily giving rise to a level of eccentricism from our mind magic MC. Mages, always tend to have that problem, don't they? And despite the work to make him seem rather dim, his investigative abilities actually counter a lot of that. Once again, Primrose and Samara pose the most difficulty in all this. At this point Samara would need an excuse to at least 'keep an eye' on the MC. Or renounce her service.
Primrose you may need to go the friends route with to help that out.
As for acceptance... well the notion he still saved the Princess via her own proclamation would be enough to keep issues down with the common folk at first. After a bit they'd do similar to what they've shown with the Evelyn's Dark Secret information; accept it. The grouping could easily end up with enough economic power via your sister's negotiation work and Callie's tailor shop. The library could be cultivated into a similar situation as a day base of operations and study for the MC, taking up a 'Truthsayer' position. Or if Nell is involved utilizing her skills for that as the MC moves to learn more magic.