>> Given that the root cause is bad installation, would the HOA share/cover the cost?

Everyone always thinks the answer lies somewhere "out there", when in reality you are the root of all of your own problems. 

The plumber gets there and discovers tree roots in the sewer line so it takes longer than anticipated and your bill comes in at $360.

I'd rather have a root canal. 

The reason this came back is 2 fold: it wasn’t actually killed to start with because he bleach didn’t penetrate like the mold roots did, and the humidity is such that it’s ripe for repopulating.

And try to look for the "root" of the issues that are preventing you from being at the sale you want to be. 

If its the same dated filter I installed at move out I'll charge the tenant for a service of the unit due to the added strain on the system they caused by not following our lease agreement.With your plumbing situation I would include a lease provision that states tenants are responsible for maintaining all plumbing, excluding root intrusion and the like.

Properly functioning sewer lines don't need "maintenance"...My guess is, it's either an old clay pipe with tree root problems (in which case they should replace it, or remove the tree), or it's improperly installed / runs uphill (in which case, it needs replaced). 

There may be a root obstruction choking off 3/4 of the pipe and all it takes is a good heavy wad of toilet paper and it jams up.

My failed expectation of safety is rooted in the frequent early morning visitors often get the wrong house on the first try, theoretically allowing for a dope head to walk into my house at any hour, the fact that the son is still at large and we could be raided by the State Police again at any moment, and the fact that the secluded nature of the area makes our side of the property easily surveilled by the other side - which is not optimal when my wife is home alone.My landlord is now seeking damages for the lost rent and has served me with an eviction notice.