I'm looking to increase my seed money for my first investment as well as pay my bills.

It's much easier and looks less suspicious to pay 1 plumber a larger bill instead of 3 different plumbers. 

How should I actually bill this?

If he sold, that is quite of bit of money to play with and your father could pay off his bills and be set up for retirement and maybe have some to leave over! 

The Water company will lien the property if the bill doesn't get paid.   

Or, at minimum, I will get to see a lot of zeros added to dollar bills, and possibly the elimination of the cent, the idea of coins. 

Are you billing first of the month and pro-rating the first month or are your using anniversary billing? 

I have a steady income of about $2000 a month after paying all bills, rent and covering food expenses, while be frugal.

So, while I think it's nice that you want to help them remedy what they seem to feel has become an untenable living situation, I certainly don't think you should also be required to foot any sort of financial bill to help solve their problem.Is Tenant B open to leaving? 

@Bill Crow, do you mean the and that separates the bullet points?