Hosting an Adult on 'Cultural Exchange' (Live in Situation)

My kids' school does that.
They have had Chinese and Japanese Teachers, come here, they sponsor the visiting Teacher, and they teach at my kids' school. And they also, speak English or other languages.
It is fine.
They reside with a host family. They come to school with host family.
And they are then with their peers- the Teachers. At, school.
They are not treated as an inconvenience, but as a part of the family.
And they are very gracious.
They have, Cultural, differences. So you need to know that and respect that.
But they are also, (well at least the one's at my kids' school), they are also very educated themselves. So, they are globally minded.

It is not difficult. And yes, your own "routines" may be different when the visitor is here. But that is what happens, when you have a Guest.

I would, rather host a foreign student or Teacher, than my In-Laws.
We have have hosted foreign visitors before. Students.
And it was fine.

It is going to be the most amazing experience for your whole family! I am so excited for you!
I think MommaBear gave you great advice. I think setting up house rules from the get go will benefit all of you. Maybe you could incorporate some of her rituals to help her feel more at home.
Good luck and I can't wait to hear about your experience!

What a wonderful opporutunity! I'd do it in a heart beat. The program she is with will likely provide a lot of suggestions and ideas for making the co-habitation work. We did something like this 2 years ago for the summer. The most important thing is to set the house rules up front so she knows what your expectations are. Things as small as how bathroom routines work in the mornings & time alloted and who will be doing her laundry to issues as large as dating and bringing home/not bringing home dates should be discussed on day one. Other considerations are food - who buys or does she just chip in? Cooking meals? Share of housework? (Again, most likely her organziation will set a lot of these rules.) Another big issue we tackled on day one was religion. We don't attend a church, and our person was Buddhist, and needless to say we are about 200 miles from the nearest temple. She was understanding and found other ways to practice while visiting us.

Start thinking outside the box as to how to help her socialize. A lot of people socialize through the church, and this might not be an option. Certainly she'll make friends at the school.

I wouldn't worry about the nanny thinking it was weird having another adult around. IMHO, if the nanny is uncomfortable with that she might now be the right person for your children.

Good luck!