Can we sue the inspector for negligence for not thoroughly inspecting the system, and allowing the contractor to fill it in when the system was not completely decommissioned?

Based on the facts presented they would be 100% negligible

The only time a property owner would be liable for the tree is in cases of negligence such as a dead rotten tree that the owner refused to move that eventually fell onto the neighbors house causing significant damage.

You aren't responsible for anyone falling regardless of age or health conditions if you are not negligent in keeping your building safe, that is reasonably safe, not customized for any disability.One thing that elderly folks seem to like to do is complain about getting old on one hand and how self sufficient they are on the other.

Here is more information.Now I get a tenant to live in this property, I need to make sure as a landlord I am covered against any claims of loss by neighbour due to negligence of my tenant.

An LLC will do nothing against negligence.

If in 2005 it were negligent in its duties as alleged , and was fully aware the suit against them, and then they chose to go forward then that was their choice within the process (not a flaw in the process itself).

I doubt my income will ever be so high that a luxury car will be a "negligible" expense.

That's a couple thousand dollars less I have to bring to closing for a negligible different in the mortgage payment.My timeline here for completing the rehab and getting it inspected and my permit approved with the city was really tight because I had committed to allowing the tenants to move in on a specific date.

You just increased your opportunities for appreciation and equity build up 3 fold, and you will harness enough depreciation/misc. write offs to reduce your tax burden to negligible.