I would have taken photos and given  her a bill that day for repair.The plumbing clogs, give her written notice that this sink is not a garbage disposal, and that grease and rice, was reason the drain clogged per your plumber and future plumbing issues of this type will be charged back to her.Same with toilet, provide her a plunger and advise excess of toilet paper is her responsibility for and plumbing calls.

You'll have a lot of questions on your journey and having the ability to bounce ideas and talk REI with someone in person is invaluable. 

I have to imagine that whatever is going on with him is seriously impeding his ability to live a happy life, and chances are strong that there is treatment that can really improve his quality of life.

2) Many of these tenants haven't signed an updated lease in years, so would that impede my ability to require them to sign an updated lease that includes utility bills?

Without more information on your personal financial situation or the property, I've reached the limits of my ability to help.  

At the end of the day, when investing passively in other people's deals, you are mostly making a bet on the team, their track record and their ability to execute a business plan.

@Christina Merlo everyone makes great points here, but one I would add is the ability to obtain gap funding through the form of unsecured debt, used for down payment, closing costs, rehab, (or anything really, since it's unsecured).

This gives you the ability to learn exactly what this'll bring in for cash flow without jumping all the way in.Plenty of options.

Even a $500 increase in rent coupled with the $3,000 for the car and you're looking at almost $10,000 in expenditures that you don't have to make and that will inhibit your ability to grow and accomplish your financial goals.I would try to sit on this for a year and see what you can accomplish. 

You claim the tenant is "stringing you along" and Im sure that is true, but you also have the ability to be VERY clear with your communication and approach.