Generally, the only widely available pathway into RE investing with low cash is via househacking where you get a primary residence loan with a very low downpayment.

For the son to qualify for the $250k exclusion, I believe he would most likely need to meet the ownership and use test, meaning he needs to own and live in the home as his primary residence for at least two of the last five years before the sale.

This would amount to about 4-5% of US residents and of a demographic which disproportionately rents multi-family and also SFRs not owns.

The problem with that is it'll be harder for the residents and the vendors to use the rentvine features as fewer people want to log in to a website from a smartphone.Also, it requires a lot of clicks/scrolling/opening new pages/tabs to get to where you want. 

I have a buddy who offered sponsorship, but he has been doing it for over a decade and maybe only sells one house a year, and never to investors.

My current asset allocation based on age and risk tolerance not counting my primary residence is 70% stocks, 20% RE, 10% cash/bond type vehicles. 

They will be your BOG (boots on the ground) to be able to view the property.I will say that I did buy my current primary residence abroad and it wasn't fairly complicated, I would just do some things differently than I had initially anticipated if that makes sense.

I have 880 credit score, decent savings, and no other debt except for 300K mortgage on my primary residence (worth $1.5 million).

He also does solar deals that are out of this world in Hawaii but you need to be a Hawaii resident to get the full benefit.. what size are those developments?  

We are looking into getting a fixer upper and plan to rent out our original residence ( Zillow says we can get $2700 median rent in our area ) while moving and fixing up the new house.