I did not choose to see the homes in person as it did not make logistical sense for me at the time, but I'm sure I will at some point down the road. 

Recognizing the red flags with Contractors is a must-have skill!

I'm considering helping on cost because they're potentially going to buy the property from me at the end of their lease, so trying to keep the relationship amicable.

Would this help me at all when it came to the tax on my flip @Michael Plaks

That could be risky too but otherwise for 2-5 months out of the year I could be breaking even or in red. 

There's a meetup--red stick investors group--here in BR that is great for meeting other people in RE and learning.

bad english is a for certain red flag of fake lender.

All of the benefits of an investment specific underwrite with non of the red tape of conventional loan! 

What are some red flags or does and don'ts when looking for and purchasing owner financed properties?

Red flags to look for are brokers offering both QM and nonQM products, such as VA and FHA loans concurrent with hard money and DSCR.At the end of the day, it really boils down to if you trust the account executive/loan officer not to misrepresent the terms for the deal.