I inherited their services when I purchased a sec8 rental property and initially decided to keep them, assuming it would be the simplest solution.

and I think there are several remedies to resolve this - and the developer and the city's business/permitting services both have liability here. 

(I understand upon learning the per is an ESA or Service Animal, one cannot charge pet rent....but these are still animals and can cause damage to the property.

If you are worried about this there are companies that handle servicing these payments automatically on a scheduling system if you have a bunch of them. 

I researched some eviction attorneys and property management companies who offer 'problem tenant' services so most likely will reach out to them.

I attended an informational training for beyond bnb, without signing up for their service, I implemented a couple strategies they discussed and found they worked.  

They are threatening to sue to try and get something from you but most likely will not go through with it as you have no written contract in place and in california there is also no non-compete agreements.

Sometimes I see properties currently for rent lower than those 3 services. 

This used to be a non-issue for FHA buyers up until 10 years ago when HUD stop allowing buyers to use their appraisalsKeep in mind your agent is not dealing with HUD directly. 

Open to out of state investing, non real estate etc?