My focus has been in Lexington because of my familiarity with the area, but Louisville seems to have more options in the small multi-family investing (my preference!).

I would talk to a mortgage broker in the US who works with foreign investors and can explain your options, but I would also definitely contact Canadian banks to see what they can offer. 

ITs certainly in the ballpark but I think you can do better most likely - especially with your experience of owning five rentals - certainly some options here on BP to shop around - but the rates and points seem a tad high - you could probably secure something with both a lower rate and origination (and potentially no appraisal cost as some Hard Money Lenders don't require them)

Looking for good options to get a pre approval done in Colulmbus, Ohio

I do not have anything positive or negative to say about them. 

It is part of the game as with any other potentially high-reward endeavor but it doesn't have to affect your well-being.That said, your vanguard account is a good reminder that there are other avenues to consider outside of RE.I'd recommend continuing to diversify by exploring other RE options.

You can pursue any of the options you mentioned, or even all three.

Identify promising investment opportunities and present them to the investors you've networked with, while also offering financing options.

You have to be in the right position to invest - and currently it seems like you aren’t there due to your recent purchase. 

@Kevin DiMaggioIt sounds like you're in a great position to leverage your existing equity and income to make another real estate investment.