Keep in mind that the demon will be a little rude, but just enough, as she likes. Emilia will monitor the reaction and adjust everything as needed.
If anything, they are taking a large healing powder, a potion of willpower (I hope you didn't fool me by mentioning it), a universal antidote, and a healing potion (I still don't trust the vapors of this Mist!). This is what the budget allows. I just don't know how and where they will sleep afterwards; I hope it will all pay off.
In short, make the transition after the events normal.
As a farewell, they will also tell her that they really enjoyed spending time with her and that they would like to spend more time with her when they have the opportunity.

