Whomever you go with put your emphasis on getting really good training.

My advice - If you buy a smaller 2-4 unit in Troy that's a good deal, just expect that it is unlikely to be a cosmetic only rehab, you need to budget on major structural/mechanical rehab in most cases so that it is solid when your tenants move in. 

The emphasis has been on either how to fix this guest's problem (run out and buy a baby gate) or how to be prepared for a confrontation (expect a refund request and plan on refusing it).Remember, we are in the hospitality industry and if we want to be super successful in this industry, we need serious customer relations skills.

The house I just purchased on December 6th has just received mechanic's lien for $15K for what I would assume would be for the new the roof the seller's put on the house prior to closing...

The cost really depends on the mechanicals they have on gas.

Have they been rehabbed with new mechanicals/etc?

What is your finance mechanism LTV%?

I then only have to deal with one lease, one set of mechanicals, and no tenant issues etc... 

Don't ask them the mechanics of it (you can find that on YouTube), ask them what their lifestyles are like, ask them what they wished they knew earlier, ask them if they would do it all over again, ask them if they would keep doing it if they didn't need the money.

I agree on ensuring they pay bills, there are mechanisms to aid in that process.