I think you need to calm down about thtis "my stuff" thinking. The Waerd have an extended family compared to other tribes. Better communication and you can work togeather more effectily.

If you do not trust this new Janouan family, why marry into it?

And im not sure how exactly it will work, but i guess if you are not 100% Waerd, you do not get the tribe advantage.

I would imagine if you left the waerd settlement and joined a Janoan settlement, you would no longer be considered part of a waerd family. So no, your belongings would no longer be shared with the waerd settlement but neither would you have the waerd family advantage.

Last concern first: the Waerd don't have free reign to "steal" your stuff. They can use your hammer without asking, or come into your house to extinguish a lamp you left burning, but they can't take anything without your permission. It is easier for them to steal your things, but it is still illegal for them to do so.

Now, about marriage. If you move outside of your Waerdic community, you lose all the benefits of being in that community: family chat, bolstering, access to community resources, etc... I think that if you marry your Janoa mate you will not earn exile--meaning you would be able to rejoin The Waerd community later if you chose--but any of your half-Janoa offspring would be strictly considered not The Waerd, and would never be able to join the collective or gain collective benefits.

EDIT: Also, if you do move to a Janoa settlement, other members of The Waerd would not have access to your home. The access rights apply only to The Waerd in your Waerdic community. Not all of The Waerd.