You really need to consult a California attorney about this. The laws are different in every state, and even though both Texas and California have community property, the common law marriage aspect is different there.

Also, you would want to ask if you need and want to be in title as parents, since to divest your title will cost money, or would you prefer just to be on the mortgage note. In either case, in order to relieve you from the re-payment obligation your son and daughter-in-law would have to close out the old mortgage loan. This is a bit messy and expensive.

As to ownership, if it were Texas, all would be tenants-in-common unless some other arrangement were specified. Your attorney in California can help you with what happens there.

So, consult someone in the area where the condo is going to be so that if you need help when there, the same lawyer can help you.

Lauribilly,

If I understand you correctly, it appears that you need a Co-borrowers agreement. This agreement has many advantages for both the parents and the daughter/fiancee. Feel free to contact me at your convenience to discuss your situation for the proper solution. My contact information is available on my web site.

You can do it several ways. Yes on both of those scenarios, but there are other options. But you do have to think about the worst case scenarios; and, what will you do if those scenarios pop up. Personally, I would recommend hiring a real estate attorney, such as Laura Fowler so that you understand the legal implications of such scenarios.
Best to ya,
Tim Moncrief
Tim@TopKWGroup.com