In terms of which Credit Card to pay off first, I have learned that in terms of your credit, your collection of cards are looked at as an total usage rate. 

Once you are the owner you can request a letter for rebuilding the subject should burn down and that will show the current usage for the subject .

You want to rent to less number of occupants so there is less wear and tear, less usage of utilities (if you pay for it)? 

At that point, as decades of case law have prescribed, we should look to the common definition or usage of the word when there is question of legislative intent. 

To add to what Thomas said, most utility companies will give credits for "higher than normal" usage.

In MA in particular, water is very expensive and if you have tenants that sneakily add in sublessers into your property and increase your water usage that can be a big change in cold water prices. 

SFH's are much easier because you only have one tenant and they can pay for their usage.

Ultimately do what feels right, Google Voice is free for the first number when you sign up with them and having Unlimited data calls and texts are technically data usage since you are using an app and you’re NOT using your minutes or texts, if you have a certain number allotted to you each month, so it’s a win win.

If someone ask you a question about zoning or usage call the city for them and do your homework .  

Look into the rules to be sure there are no restrictions on usage.