How can I make potential tenants feel at ease when reading listing, to legitimacy of offering so they feel secure in dealing with me, putting deposits, etc.

And if he/she files your taxes appropriately and declares your rental income and depreciates the property you will be committing fraud.Your primary residence is where you live. 

Do we have to file it with the state first? 

We've taken the first steps to secure the land. 

I pay interest on the money while it's in use, secure it with a note and deed of trust on the property, and then split the profit's 50/50 or in proportion to the amount of the investment compared to the total cost. 

I would just call them and find out what the note is for, then file an appeal for your taxes.

If you been filing US tax returns while in Japan (legally you should have) then even with a lower credit score you could possibly get a loan. 

I'll be working for Security Bank, an under $1B bank focused mostly on CRE, IRE and commercial lending.

The following is why I am a little lost:If I were to have my mom sell me the property, she will have to report the income for tax filing, and she is currently unemployed, and getting government assistance (I don't want to mess anything up).

First off, I think the Tax Court would view such a transaction as “running one’s personal services (here brokerage services, aka putting buy & seller together for a fee) through a Roth”, treat the profit on the “assignment” of the contract as personal services, treat the money in the Roth as an excess contribution, and penalize the taxpayer for failure to file the excise tax return (Form 5329) & failure to pay the tax thereon.In light of this case, I think that the Court would certainly view an IRA with an assignment deal as “not at risk” – all it has in the deal is $100.