That being said, it’s currently being rented out below market, and the numbers work with the current listed rent (assuming it’s accurate of course I’d verify this).

Revenue Stream:  Again verify with real estate agent$ 2,160        This location is off the track and old. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Set aside 1 hr per day to make at least 5 calls with verifiable information.

1) Get copies of current leases, do NOT take a broker ProForma2) Get copy of ACTUAL income & expenses3) Do your own math and have broker send you comp sales to verify pricing4) Make sure you have an inspection contingency on your offer and hire an inspector that knows what he's doing to determine CapEx stuff.

Verify the leasing situation. 

He can have someone call the phone with Facetime and give you password to verify all if it belongs to this person.

By law, if it's your primary residence, they must verify that you have enough past, current and future "INCOME" to make the monthly payments.Cash in the bank is not considered INCOME.

How do you verify foot traffic data?

In either case, you should verify that you are eligible to transfer the funds from your existing retirement account (e.g. if the funds are in your current employer 401k, you will likely not be able to transfer until you quit your job).Considerations in Setting up a Solo 401k to invest in real estate:1.