The 1st question on condo's is always, are they warrantable or non-warrantable?

While Missouri does have a "Warrant of Habitability" default assumption for rentals, it doesn't excuse the tenant from paying rent unless they follow a detailed process. 

Essentially, if it's not in premium condition, they can warrant a service call and the associated fees.Be careful when you confront them on it because you need to consider their defense.

They will pull charges for service calls, sure, but you should limit the extent and conditions under which a service call is warranted.

The owner passed away 10 months ago, with no will.Apparently his son made an attempt to take over the house but with no will he never got anywhere and then had to hastily leave the area due to an arrest warrant. :-)Taxes were paid in the Spring, but I'm assuming no mortgage payments have been made this year.

For the second it's a No.For the first even if it is not required you would want the additional work documented with the county record so in that case it would probably warrant a permit as well.

He said that the request for a PA would warrant only a soft pull (SP).

Still no rent, file detainer warrant. 

The up-side to this is that when you come across someone who wants to sell, but they are not in any situation that would warrant a quick sale or other situation where they are willing to trade money for time and/or convenience, you could offer to act as their agent. 

Trusting their numbers at this point, all 4 warrant an increase of $100+.