Just like @Steve Milford mentioned, make sure you have an emergency fund of some sort for unforeseen repairs & also figure out that baseline for your W/S/G. 

Try to connect to property managers to understand what sort of tenant will live there and make your judgement, after numbers making sense.

We would never accept a contract where the buyer’s preapproval was only from some online company (rocket mtg being the worst, and a non starter for us).

Its whatever your lender, usually some sort of private investor or perhaps a local bank / credit union.Good luck.

It may be the case that Californication of supply is sort of going nation wide thus why some new tracts are already bought up?

In the worst-case scenario handing back the deed and your risk of loss would be low.

It brings the worst tenants.

Decide if you want to keep the tenants or if you want them out and then either write new leases or see if they are willing to move and worst case, start eviction proceedings.

So the optimal income path from an investment perspective is, what sort of a job will get you into the highest possible pay early on for the least amount of education or certification or credentialing investment? 

Most in WF are your Chuck in a truck sort of fellows.