No definite answer(s) to your question(s) can be given through AnswerBank. The conditions upon which a mortgage is set up, whose name appears on what, etc, etc are at the sole discretion of the lender, nobody else. They will arrange it in such a way that in the event of a default in re-payment they can obtain possession of the property with least trouble and sell it off to get their money back. They are the ones that decide. The lender is by no means bound to agree, but should they do so whether your friend and his tribe hold the property as a joint tenancy or TIC may be left to them.