In response to your question(s);
First, I am going to ignore all other issue(s) and only address the specific issue(s) you had a question about.
Yes, you are allowed to deduct the interest and the property tax(es) paid. The fact that you will be living abroad, ex-patriot, does not change the tax code for the deductibility of the interest or property tax(es) paid. This advice applies only to Federal law. Your State may have different rules.
My advice to you is to find a competent tax professional in your area, who has experience with people who work abroad.
Huntington Beach, CA