If the property cash flows well enough to cover the lenders debt service coverage ratio, and you have adequate liquidity, you should be able to qualify.

I was going to just request a HML for just the purchase vs. the 70% ARV, as I can cover the entire rehab with my own funds but the cost difference does not seem to be worth putting up the extra $17,000.

You covered various topics which need in-depth discussion to understand.

These are the only 2 I've read cover to cover:Long-Distance Real Estate Investing by David Greene (Loved It)ABC's of Real Estate investing by Ken McElroy (Interesting read right after the above because he has a different view)And I'm in the middle of a few others:The Book on Rental Property Investing by Brandon TurnerThe Complete Guide to Real Estate Finance for Investment Properties by Steve BergesMulti-Family Millions by David LindahlThe Millionaire Real Estate Investor by Gary Keller

I do own all properties under my personal name (liability is covered through an umbrella policy).

This is a topic for each investor to cover with prospective management companies before hiring one.I know of at least one management company that recommends the owner pay for the renter's insurance (with the cost folded into the rental rate) and advertise that fact as a marketing matter. 

If you get a written cancellation from the buyer you should be covered.

Maybe i'm misreading but when you rent out their house, the first 670 should go to them to cover the mortgage and then you split the profit? 

Is $100/month/per unit enough to cover costs associated with turnover of a unit?

The APIs are not too tough to use, and I would recommend picking a handful where you'd get the highest value and trying to build out a small MVP that could do those for you.AdWords are also a decent outlet for your existing sites, but I imagine you've looked into that already and maybe even have it covered.