The GC hired an electrician for a complete house re-wire and a plumber for a complete house re-plumb.

Whether it's a plumber, property manager, insurance agent, or title company, lean on other real estate investors that have worked with them.  

I’m a decent plumber, electrician, lawn care, and she does all of the hosting at the short term.

Our plumber re-plumbs entire houses for much less than that, and if it's a simple leak you can find, you could be done for a few bucks.The 80's were the era of pinhole copper, so there's always a chance that your supply lines are shot when buying a house from that time period, but it could be something minor too.

I've been a licensed real estate broker in the past, have taken the appraisal courses, but didn't take the test, and now a licensed contractor and plumber, and soon to be electrician and hvac.

Please find someone else more reputable.

I knew I needed to become an expert in order to get the right investors and build my reputation.

Customer reviews are the backbone of a company's reputation.

All I've gotten is the secondhand knowledge that she would pay for the plumbing issue (her plumber quoted much lower for the job than the plumber my PM/Contractor showed the sewer scope too, and no plumbers have been in yet to look at the issue in person, should happen Monday.)One last question which i will also attempt to research on my own, how would i best find the land value?  

Also same as any content created anywhere else: maintaining your reputation as an expert and attracting potential customers/clients/partners/lenders/etc.3.