In the aftermath of the storm named Sandy, insurance companies have sent out inspectors into the the field to examine properties.

Decide whether the tree is aesthetically pleasing and adds value to the property, or if it would be better to take it out and make a change to the landscape design.Hire a qualified arborist to examine the tree and give a professional opinion about it's health and whether it poses a danger to property or people.If the tree passes muster, then ask the arborist for guidance on how to best take care of the tree.

The first deal is going to be the most nerve racking.

The medical examiner will make the call.

I don't know anything about California law but to answer your 1st question you will be able to gather more info on the renters during your due diligence process i.e. rent roll, examine current leases etc.

Good idea to gauge your homes water system is to remove an aerator from a faucet, just unscrew it by hand and examine what you find lodge in the screen, might shock you.

In many cases, you can’t examine the property from the inside and have to guess on its interior condition.You can get stuck with a house filled with building violations and environmental hazards. 

If you are having a hard time finding deals I recommend just taking a step back and examining what you have and see if you can just make your own deal.

But your tenant was concerned, and they did the right thing by contacting you and you did the right thing by getting someone out there to examine the issue.

(I actually brought ezlandlordforms.com to their attention, but in vain.)There is a section in the contract that says this:"POSSESSION: Tenant(s) has examined the condition of the Premises and by taking possessionacknowledges that they have accepted the Premises in good order and in its current condition exceptas herein otherwise stated.