I want to help my son get off to a great start but I am also concerned what cosigning will do to my debt to ratio and I have been circling real estate investing for the last few years, ready to take a shot now.

Since I am just starting out though, the interest that I'm will to tack on to the 20% private loan is 3% interest.

So he started his own club.

Oops, I totally forgot to add that. 

Not sure what state you intend to get licensed in to start, but before you get too far along I would check with the Real Estate Commission to confirm that your end-game (AI decisions only, no human broker in the loop) will pass their muster.

I will start with open, face to face convos.

Due to item 1, adding an ADU can require years to start achieving any return (once the accumulated cash flow recovers the initial negative position).4) Adding an ADU is a slow process.

Got any advice for someone who's still in college and wants to start rental property investing as soon as they graduate?

I started out with single family houses and hated it.

The eviction process should have already started unless monthly rent is $4300.