My wife and I have different appetites for real estate investing and have not found a professional that can help us work together to understand the key questions we should be asking ourselves and help us sort through all of the options.

With that said, it all comes down to your goals, your risk appetite and sufficient reserves.

HELOC on the TH you're living in sounds the most doable (banks have more appetite to lend when it's owner occupied).Two cents - HELOCs can be great, but it is still debt and you'll want to make sure your base case expected return makes the juice worth the squeeze.

LTR's are about 6% - 7% cash on cash (14x - 17x GRM), I just don't know what the STR investor appetite is.

Many will not have an appetite for them now.

Appetite, capability are different for each person.

I myself don't have a lot of appetite for risk which is why I started investing in real estate.

They also have a good understanding of different lenders' appetites, and thus can save time by filtering out lenders that won't be competitive. 

His attempt at suppression has failed and the video has been restored. link? 

-- depends on your risk appetite but leverage can certainly pour gasoline on your real estate investment fire in both a good or a bad way.