Since the price of a multi unit is double or sometimes 3x the price of a single family home, would it be smart to start off with a SFH and scale up from there or just make the leap into a duplex that I can force some appreciation with minor repairs.

I am at this point looking an easy/smart way to put something in between.

Here are a few suggestions on how you can maximize the wealth of information available: Check out the blogs and podcasts, or take advantage of the search feature (magnifying glass).

If a family with kids values D+ then the probably already have it, so providing smart TVs where they can log into their subscription is sufficient. 

Detroit can be a fantastic market with strong cash flow and good appreciation potential, but it’s definitely a unique place with its own quirks.Starting with cash is a smart move, especially in Detroit, where local knowledge and relationships can make a huge difference.

Also, would a home warranty be a smart move?

Ditto, I use PriceLabs for my STRs - here is a nice writeup ...Airbnb Smart Pricing Vs PriceLabs: An In-Depth Comparison For Hosts | Boost Your Short-Term Rentals

If you were in my shoes, what real estate strategy would you recommend for scaling quickly (but smartly) so that I can replace a good portion of the W2 income from real estate investing?

It sounds like you’ve got an exciting plan mapped out, and I love that you’re thinking of starting a property management business while building your own portfolio—that’s a smart move.

Absolutely, real estate can still be a smart investment—even in this market—and the Panhandle is one of the best areas to consider right now.