How serious is this pattern of denying claims? 

Is this pattern will work on DC or there are a lot of hidden rules and regulations need to pay attention.

The triggers of a recession are irrelevant because the financial cycles are the product of mass human psychology; a self realizing prophecy based the belief of patterns and that what happened in the past repeats itself.

Odds are there is a pattern you might be able to useAnd if she has a trail of wreckage maybe banding your damages together is some kind of leverage?

This is good for the Renter and Home Owner but the day of reckoning will eventually come.I have been tracking Foreclosures and REOs caught in a holding pattern waiting to be auctioned some time in the future.

This is one of those vague threats of taking action against you if you attempt to enforce your rights.Any one of these I would let slide on its own, but taken together, this is a pattern of behavior that will not improve with age.First thing I would do is offer to release them from the lease because of the concern they recorded over the rain findings without penalty for early termination.

The Owner determines that there is reasonable cause to believe that a household member’s illegal use or a pattern of illegal use of a drug may interfere with the health, safety, or right to peaceful enjoyment of the premises by other residents.

No  one will get rich this way, you have to put in the work and do the time on your own, you are the only one who can control your behavior and work patterns, and the only one who can make your life better with your choices.  

And TBH, I am also a bit fearful that fighting this would cause them to find an issue and not give us our deposit back.Another pattern in this thread has been how useless home warranties are.

I'd put a nice carpet runner up the treads, it will protect the treads and should be fairly cheap; pick a good wearing but modern pattern/color for the carpet.