Since the old lease with the old landlord was still in place, he says he is not responsible for that damage ... and that in fact, it is not damage ... that it is just the cost to a landlord to clean it up.

The home is structurally sound with no signs of mold, however the electrical is rather dated.

I could do general labor things like painting for example, but when it comes to electrical, plumbing, etc...not so much.6.

Third, the seller may die or disappear, leaving you with a legal mess that will take time to clean up.See a great lawyer with experience with MLOs.

I need the following trades - tile, framing/drywall, painting, carpet install, maybe a little electrical.  

I live in FL so I know about having to use A\C year round.As you know people mention a brand and price but not model which will ultimately determine the total cost.I was in the exact same situation and due to the rusted coil tubing, and overall condition of the Air Handler decided for a total A\C replacement.Payne is considered "Builders Grade" lowest grade and some A\C guys argue not to install them because it reflects on their reputation when you have problems with the system.Look for the highest seer rated, quietest, best warranty HVAC that is fairly priced.The installer is a HUGE part of the HVAC's life span, along with your regular changing filters, cleaning coils when needed, cleaning drain lines and vacuuming dust out of the Air Handler Cabinet.

There is a local guy who handles lawn, snow, and unit clean up who has a check mailed to him once work is completed.  

(Make sure you do not go cheap and undersize your ac unit, you'll regret it later in maintenance calls or complaints of it not cooling the house off enough when it's triple digits and 75% humidity) If you need any wiring done, check out Bybee Electric - they'll get it done quickly and efficiently.  

Offer a cold drink on the hot days, hot drink on the cold days, help keep the property clean, even help shovel snow from steps.

Owner pays w/s/g and tenants pay gas/electric.