Thank you for your reply, but you wrote a lot incorrectly.
Maybe this information will be useful to someone.
Issue #1 to submit form 751 it is NOT necessary to live in the USA.
Issue #2 It is not necessary to have housing. Other connections are sufficient, including paying taxes in the USA, this is the important one that they take into account.
Issue #3 You must have a postal address in the USA (we have one). USCIS sends correspondence abroad only if it is an informational letter. For example, USCIS sent us a letter to Germany stating that my Reentry Permit is ready, but they do not have the right to send documents abroad. Therefore, they asked where in the USA they can send us my Reentry Permit.