In fact, we keep up the mowing, etc.Yes the tax lot # is listed, the sellers agent sign was in the yard of the house, with what ended up being our Agents name and number listed.  

You'll also want to set up some house rules because technically, you are renting out a room and they have access privileges to the common areas like the kitchen, LR, FR, laundry, yard, etc.

There are commercial products that can kill the root of the tree and not harm the rest of your yard. 

I'm trying to improve the property as the current tenants have stuff all over the yard.  

You could look for other indicators, I was listening to a BP podcast the other day, I'm sorry I don't remember the number and the guest was talking about his best performing mailing lists and he liked owner-occupied high equity owners, he also suggested going onto craigslist and looking at the yard and moving sales listed in your area, get the address and find out if they are owner occupied.

Since there was a small amount of dog poop (we'd been there the week before, with 1 small dog, in a tiny yard, like 30x15), the landlord did need to pick up the remaining poop there.  

But, for the rental property, I just called an exterminator and had him spray the yard and the yards surrounding the yard, since I owned them as well.

They wanted $2600/month in the lease purchase.Is there anything salvageable here creatively?

Ours was one unit in a three-decker in Dorchester and the condo fee was very reasonable, probably because it was self-managed and the owners pitched in to do basic tasks like yard maintenance.  

For the little rental back there to give them their own parking spaces without coming through the back yard.