Do you only accept tenants if you “think” they can pay their bills and just as an extra safety precaution you get a co-signer?

In the right short-term situation where you can buy them out quickly by refiing the property as you suggest I think it works well but those deals are very hard to find for people with deep experience and connections in that local market so for someone with no experience and no local knowledge it's going to be nearly impossible.

Aside from being responsive and knowledgeable, she is also an experienced landlord and property manager and an expert in lease/purchase and owner financing.

I budgeted for extra strips, just in case mistakes are made or we discover some imperfect strips during the installation process.

I am looking to learn, network, and ultimately grow my real estate knowledge.

Being a real estate agent is 95% marketing and 5% knowledge of real estate.

If you believe in their knowledge and you're very close with them, then maybe they're steering you in the right direction.

I could also pay more monthly cash out of pocket as my finances allow it but I'd prefer create cash-flow and put that extra cash into other savings or investments.Any other pros and cons of shorter vs. longer term HELOANs?

Welcome and this site is a wealth of information and knowledge, my suggestion is read, read, read then get started! 

Long story short, her dad took over and I started paying him rent for the room I was in along with some extra for bills and what not.