If you want title insurance and want to be safe and want the easiest situation to resale, let the title company bless this....not the brother.Possible probate is not needed...possible probate does not take a long time...4-6 months. 

Trying to help a friend plan - he's got a (3 units) rental in Northern NJ worth about $800-850K (his father transferred it to him as gift or $1 back in 2007).

The easiest way is from your Realtor or a title rep.

https://www.fbi.gov/scams-and-safety/common-scams-and-crimes/business-email-compromise#:~:text=In%20a%20BEC%20scam%2C%20criminals%20send%20an%20email,gift%20cards%20to%20send%20out%20as%20employee%20rewards. 

@Corey McNabbThe “easiest” way is to build a team of people who know the answers to your questions.

Let's face it, the way you've described this your friend has no involvement in this deal.With him providing the cash for the down payment, your lender will see this as a gift from him to you. 

Also our HAs here are easiest to get reach via email - have you tried that?

Once we have the note signed, and my investor gives me the capital for the down payment, is this just considered a 'gift' I put into my bank account and must be filed and taxed as a gift payment if I want to take out the mortgage under my name?

VA Loan made 0 down the easiest part!

Lease option would probably be the easiest in this case I would think if the mortgage is not assumable.