Title III of the ADA requires the removal of architectural barriers in existing facilities unless it can be shown that removing the barrier is "not readily achievable."

To add value to the property, we undertook extensive renovations including the removal of over 40 yards of trash, installation of a new septic system and wall-hung boiler, and a new well pump.

It sounds like you have an un-permitted unit, which is essentially always a risk since there has been no notice to the AHJ that it exists and they can therefore initiate a code case to have it removed in most cases.

@Adedayo Adetunji people that break into a property & occupy it are called "squatters".On September 24, 2014, three new Michigan Statutes went into effect to make squatting a crime and give landlords more options to remove them (see Michigan HB 5069/PA223, HB 5070/PA224, HB 5071/PA225).

If you hire a Property Manager they can sometimes help arrange lawn and snow removal service.  

I'm considering new floors, fixtures, countertops, windows, removing popcorn ceilings, etcetera.

I frequently see where one party is awarded the property and debt and is mandated to sell or refinance it within a certain timeframe to have the other party removed from the note/mortgage.

To add value to the property, we undertook extensive renovations including the removal of over 40 yards of trash, installation of a new septic system and wall-hung boiler, and a new well pump.

My hope is they will be removed from the property prior to 2/15 but, I'm worried if paperwork was done incorrectly (I don't believe it was) and I need to start the process over again, I can just fall back on the 30 day notice.

There are also removable barrier fences and alarms that people use instead of permanent barrier fences.