I am not licensed to do so and am simply offering my opinion for free, based on experience and anecdotal evidence.

Initially we were going to simply flip it, but then the market began trending in a direction that supported holding it for a year. 

How much of that 50K would need to be spent simply to arrest the downward trajectory of the business as it presently stands?

After many attempts to pick-up where I had left off with her I moved on from this one and flipped a home up the street instead.

And of course you could simply look at MLS deals and realtors.. you just need to buy a home that either already has a tenant and just do your normal inspections. or one that has had recent reno's and again do an inspection.. the turn key provider is basically just a rehab flipper of rentals..

Tying up valuable marketing time then simply not performing on a contract is not something to be taken lightly.

Or can I simply right that in as a clause? 

Like @Ann Bellamy mentioned, my lease also specifies that all payments will be applied to outstanding fees before being applied to back or current rents.What I am unclear on, and I would greatly appreciate input from others, is whether or not I can simply send updated lease verbiage to tenants whose leases have expired (and are therefore month-to-month), without getting their signatures, or if I have to take the time to approach each of them individually and get them to actually sign the new lease.

But as a former smoker who tried to quit about a hundred times before finally succeeding (anyone interested in quitting by the way, check out Allen Carr's book The Easy Way to Stop Smoking, it's quite literally a life saver), if your rule is to not allow smokers, the odds he will quit on this attempt are remarkably low (unless you give him that book maybe).

One just simply paying off the 0% CC monthly minimum and balance transferring to the next 0% card over and over.