$40k into the deal with down payment, closing costs, replacing furnaces/adding AC, and a couple misc. items.

Our leases as a management contract try to hit just about all the items that could go wrong.

I already gave them one warning about all of the above items ("excessive noise", unauthorized pet, parking violations, trash, all in one warning). 

My thought was that she was helping them place/rearrange their existing items....although, it seems like her service could be malleable.

It sounds like you have replaced all the big-ticket items so there shouldn't be much else to break. 

I've worked in property management for 2 years now and it's really helped me gain a better understanding of the industry, and has been helpful studying for my broker's exam as I've encountered many examples of items I'm now formally learning about. 

You may also find that your client is looking for a unicorn and may decide it isn't in your best interest to start the hunt with them.As far as data goes - I don't think you will find one source of information that combines the items you are looking for. 

. - Drainage Report/Analysis could be a big cost item depending on the governing agency & what the stormwater requirements are.

It is exciting, especially in a bad part of town....adds to the mystery and suspense...and you get to carry a gun in your truck every day... :-)But seriously, if you are not an experienced builder or have some decent skills, you will be eaten alive by a project like this.

What you really need to do is look at all the items in the property that need to be or will need to be replaced in the coming months/years and figure out how much money you need to set aside every month.