If you're going FHA you'll be looking at duplexes because of the self sufficiency rule preventing you from looking at Tri's or Quads. 

I wanted to use that line to purchase and rehab a property for the in-laws before putting it under long-term financing but come to find out that there is a term in the agreement that prevents the line to be used on a property for family members.

What are some rookie mistakes that are made and how can I prevent them?

I want to buy property with feasibility study, and I want to prevent him selling to somebody else while I am doing feasabilty study. 

Having said that getting a perspective from a trusted broker that truly understands the NNN lease market can be worth the fee in order to prevent buying a dud property.

Watermarking your photos may be a good way to prevent scammers from taking and using them.

Which assets in a home do you always make sure to follow the manufacturers recommended preventative maintenance schedule?

It prevents me from stagnating.

Long story short, I have more than 10 mortgages including a primary and it's preventing lenders from working with us to refinance, cash-out refinance or even take out more loans. 

This is because electric bills aren't very high, and you pretty much need to run the AC 24/7 to prevent mold.