However the zoning ordinance only addresses the "character" of the neighborhood (unit density, setbacks, lot coverage, etc.), while the building code deals with the safety and habitability of the structure. 

Those things are nice, but character and depth of track record count for more than those things.  

We've been attempting to discover a permanent resolution. 

Stand your groundI recently had a tenant attempt the same thing over flies in her apartment. and I had one try it because a mouse was in her unit.

At this point who would I contact in attempt to acquire the property?

Put in three shower/commode/sink/kitchen, etc units.If this place has character and the right neighborhood.  

There's an attorney in Orlando who has a great website devoted to this exact topic that is a must-read: https://www.richardhornsby.com/crimes/regulatory/u...It states: "In Florida, it is unlawful to engage in the following real estate related activities for compensation without possessing a real estate broker's license or sales associate license.Advertising or marketing another person's timeshare or property for compensation.Auctioning or attempting to auction another person's property for compensation.Buying or attempting to buy real estate on behalf of another person for compensation.Listing another person's timeshare or property for compensation.Operating as a real estate broker or sales associate without a license.Renting, leasing, or attempting to rent or lease real estate on behalf of another person for compensation...The crime of Unlicensed Practice of Real Estate is a Third Degree Felony and assigned a Level 1 offense severity ranking under Florida’s Criminal Punishment Code.If convicted of Unlicensed Practice of Real Estate in Florida, a judge can impose any combination of the following penalties:Up to five (5) years in prison.Up to five (5) years of probation.Up to $5,000 in fines."

For right now I am more focused on the condemned property due to being able to renovate rather than new build if I keep an existing wall and a failed attempt to have a use variance for the vacant plot to make it eligible for a multi-family property.The mistakes I made for the vacant property were just endless and took about 6 months to come to fruition.

As a landlord, and already attempting the obvious "let's snake the drain" move, do you just hire someone to fix it, or continue to ask her permission to stop by and try home remedies?

The wood boards add character, with paint you can choose any color you want, and if the boards are in good shape, paint is surprisingly durable, especially if kept up with some light maintenance every few years.