I'm only licensed in California and haven't / don't care to validate this, but people credible to me have claimed that wholesale lenders (who we work through as mortgage brokers) bump their rates significantly in markets where the real estate is cheap.

I also hired someone to convert my stove from gas to propane because I just didn't feel comfortable doing it.

Not saying anything is wrong here just really curious to if this is really a valid strategy and what safeguards did you have in place to make sure you would be comfortable in doing it?

I think the central air control is only one too. Should I install additional thermostat on the renting unit and better separate the meters. The house is located in Stanton Island NY

There isn't a hard and fast rule and everyone will likely have valid opinions, but this is my opinion. 

The gas makes sense because I am still paying less than a $500k mortgage with rent and gas.

Looking into house hacking a Duplex but noticed some only have electric metered separate, leaving the owner to pay gas and water.How much of an emphasis should I place on the home having completely separate meters vs only electric?

Debt service is not calculated with NOI.You will want to bill tenants for all utilities: Water, Gas, Electric, Garbage, Management fee. 

Sometimes when you apply for a commercial loan as a borrower on an individual basis and the lender insists that you form an entity so that they can get a personal guarantee, the validity of the guarantee can be attacked on the basis it is not a"true" guarantee.

This strategy is valid, but is more complicated than what Clint covered in his 5-min video and not without risks or drawbacks.