If you plan to buy in your hometown, buy a 2-4 unit, and live in one of the units.

I've had pretty good success the last couple years with a combination of house hacking and building Accessory Dwelling Units.

No management costs as it would be self managed, and estimated property taxes by the average of the past few years.

Those are always good because your unit can get on the market again faster and the tenant usually leaves in an orderly fashion.NJ is an attorney state.

I am currently living in one of the units and renting the other one.

As others have said, the best thing your son can do is run far from this deal, buckle down, save his pennies (he probably already is doing this), house-hack, and improve a property with sweat, hard work, developing a DIY skillset, and self-managing tenants. 

Aside from arbitrage, I am looking into multi units.

The are 3 bedroomsAssuming these are in Charlotte, the rents seem very low for 3BR units.

Hello Justin,  I want to start with multi-family buildings with 5-9 units max.

Quote from @Simone Montague-Jackson: You can house hack with up to four units.