She's not going to have any leg to stand on in court if you get that far unless there's some explicit language prohibiting the owner from assigning responsibilities to another legally authorized party, and I'm guessing there isn't if another PM company was maintaining the lease and provisions - and the fact that the tenant was voluntarily working with the other PM confirms the acceptance of an authorized agent even if it's not explicitly stated, the same way if you accept rent from a tenant after a lease expires you imply acceptance of the lease terms continuing (which is why you should always have a holdover provision). 

Market Complexity in Different CitiesReal estate markets can vary significantly between different cities and regions in Germany.

The process for commercial properties is basically the same as residential properties, so it takes work.Again, echoing Dominic, a good investment is a good investment, whether you spent 8 months courting an owner to get them to sell to you, or whether it is on CBRE/Cushman/Marcus/Loopnet or any other brokerage website.  

I'm new to real estate investing in general but excited to learn about all the complexities, intricacies, and varieties. 

On literally every corner there's a new construction project for huge apartment complexes and there's tons of inventory.

Zach called me and told me they were changing my loan because they were going to consider my loan a “new construction” as oppose to an existing structure rehab or even complex rehab (considerations I’ve experience with other lenders).

This sounds complex, and if the conclusion you're coming to is mortgage fraud, I would not recommend it. 

Self-driving cars are potentially amazing, but they need to capture a lot of nuance and complexities.

I suspect it would require a court order to be able to show that you have not followed this law assuming that you have the money to pay the tenant their deposit at move out. for me, i would likely ignore this law.  

Not worth time & effort to go to court, your first meeting with an attorney will cost you as much as the rent.