Now that she is refusing to pay any rent at all you have two potential grounds for eviction, failure to pay rent or owner's own use given your plans to move in and renovate.

Though I'm no expert the logic presented above does not ring true to my gut feeling and on the ground observations, but I could be wrong ...

We are trying to reduce sound transmission between our ground floor and the second unit apartment, both of which are completely finished.

So your taxes are much lower because you don't really own anything other than the ground that the building is covering.

The warehouse I dealt with used to be a metallurgy factory that had a potential of seeping metals into the ground, luckily the owner got an exemption from having to dig up acres of concrete to see if it was going anywhere dangerous, it also helped that he upgraded his building to be as green as possible.

They filed a motion to dismiss on the grounds that the 5 day notice was served on the 5th of the month and the rent was due on the 1st of the month and rent would not be considered "late" until the 6th of the month. 

When the successful applicants missed the deadline for remitting their security deposit, we re-listed the property for rent and send them an e-mail with-drawing our offer on the grounds they had not fulfilled their obligations.

Acquisitions team, renovation crews (fully licensed and insured), Property Management, and a Real Estate Investment Brokerage in case you ever decide to sell.By teaming up with a solid firm you can mitigate your risk and have some "boots on the ground" that have your best interest in mind. 

Actually looking for a trust worthy individual we can trust to have some boots on the ground for this new purchase there.

Make sure you are comfortable with the areas and have some boots on the ground who you trust that can look out for your investments from time to time.