You must be 100% sure you have mastered your personal finances before you tackle a rental IMO, and you will know you have mastered personal finances when the money you need to invest accumulates in your bank account.

If you don't want to tackle understanding ADA I would hire and Architect as they deal with this on a daily basis. 

Pest control is not a big issues, everyone knows that their services are expensive but if both will share the pest control cost then both can tackle pests problem easier and can live happily.

How do I tackle raising his rents?

You and your email ID quickly become spammers and get sent directly into the trash, and that can be done without downloading the spam to the computer.Lists are rarely up to date - - I still see email to an email address I dropped 7 years ago. 

If you want to move one into a HELOC and tackle it there, fine.

On the contrary, there are multiple blogs I get spammed with that stress the importance of income, credit, and cash for deposit.

Of course, I am sooooo tired of getting all the spam phone calls.

Enough expertise to give you the confidence that you can tackle just about anything.I'll see you around in the forums.

If you know what you are doing, go build, if not, maybe try to build a single family first before you tackle that animal.