You can have family money. 

I'm strongly considering going prefab on a couple of lots ... if the price is significantly less expensive than regular construction. 

Unfortunately, as a lender I find most people only look to buy when they absolutely have to, often it's when they have a growing family and don't want to rent out other rooms, or live in a one unit of a mult-family unit.

Again, I strongly believe this is far from over and it would not be prudent base investment decisions on this initial ruling.

My plan is to purchase single family homes and rent them out using the BRRRR method.  

Commercial is for business purposes.In most zoning, you have residential, multi-family or apartments, and commercial, but apartment use is not the same as commercial. 

I'm new here and I would love to be part of the family.

I strongly suspect your best move is to roll the TSP to a Traditional IRA and convert the IRA to a Roth, using non-retirement dollars to pay the income tax, even if you have to borrow the tax liability.

Investment Info:Small multi-family (2-4 units) buy & hold investment.

Attend your local REI meetups to build up a strong network and feel free to reach out and connect with everyone in the community.