Good Evening,From my experience there isn't too much difference here, some cities take things like code violations much more seriously than the counties do.

If their lease is up for renewal or they are on a month-to-month, I would give them a notice of non-renewal and get them out.If they are under a term lease, I would give them notice of the lease violation (renovations without permission), and I would require them to hire a licensed, professional contractor to return the property back to its original condition within XX days subject to my inspection.

Do you have a clause about illegal actions of occupants/tenants, whether convicted or not, as a lease violation leading to eviction? 

You can stretch out the process if you get a court appearance for the work done without a permit violation.

Did the real estate agent violate any code of ethics or standards of practice under the following fact pattern:Seller listed a property online as a for sale by owner.  

The ordinance likely is unconstitutional in two ways, the judge wrote.First, the landlords argued that it violates the 5th Amendment, which prohibits government from taking private property for public use without fair compensation.

You can always non-renew and also seek to evict for violations of other lease terms if applicable (i.e. damage to property, nuisance). 

The more you can get in writing and prepare in advance, the less time you'll waste trying to figure things out on the fly with a tenant trying to manipulate you into violating your policy.

The notice must be provided on the same date as the eviction notice, or, if no eviction notice is required by law, on the date that the eviction action is filed.And, the kicker is that this must be in writing (on paper), not via email.Here is the crux of what the rule does:Debt collectors who evict tenants who may have rights under the moratorium without providing notice of the moratorium or who misrepresent tenants’ rights under the moratorium can be prosecuted by federal agencies and state attorneys general for violations of the Fair Debt Collection Practices Act (FDCPA) and are also subject to private lawsuits by tenants.As an interim final rule, this would take effect on May 3, 2021.

Sounds like you might be violating the right to reasonable privacy a little...as long as he pays, who cares....do your inspections yearly or whatever