A simple, low hassle way to bill the tenants for the gas would be to (a) estimate the average monthly cost of gas and divide that amount by 3 & charge each tenant a flat utility fee (b) bake that average monthly cost of gas into each tenant's monthly rent (c) bill them as @John Warren stated although I think some tenants might complain if a particular monthly bill is higher than usual and they might point the finger at the other tenants.

I have been DYING to connect with other RE & FI ladies.

So, my question to you all is, should I just buy the new re-branded v3 Smartthings hub and cross my fingers or what solutions are you all finding to be easy to use, manage from afar, and reliable? 

With taxes and liability figured in, that's 3 fingers pointed towards paying off your primary over rentals.

Fingers crossed for your first deal!!!

Moreover, getting rank isn’t always as easy as snapping your fingers.

In one unit, my cleaning lady sent me a picture of two small empty bottles Jägermeister that she'd plunged up from the toilet. 

Double coverage seems like a waste of money to me and a possible finger pointing fiasco if a claim happens.

The lien was against an elderly lady who owned the property and passed away.

Keeping my fingers-crossed for you that your able to close on the 4 unit.