Although this first property isn't allowing me to quite my day-job, the knowledge I have learned from screening tenants, performing small fix-it jobs, and ultimately finding/funding the deal has been PRICELESS.

I mean really man Just get rid of the guy And try to do a better job screening .

You can do your own screening of properties without an agent. 

Do you just need a software to push your listing and help screen applicants?

The biggest thing with rentals is screening tenants.

Also I need to learn the legality of being a landlord and how to go about tenant screening.

I screen my tenants carefully and one months rent has worked for me in north county.

If you are simply contracting a GC, then your value add is considerably less.Once the property goes into service, if you are going to be the PM - find, screen, place, & manage tenants -  then 10% of effective gross revenue would be fair on a single small property.  

I was outside installing gutter screens and noticed a torn window screen and a slightly open window in the common area.

This should be done before you buy your first property but defiantly before you look for a tenant.You need to be especially diligent in screening as you are going to be dealing with the bottom of the barrel tenant pool when it comes to renting mobile homes.