Life events include, but not limited to, death, incapacitation, injury, incarceration, divorce, bankruptcy, suits and claims from inside the corporate structure or outside of it.

So not only do you pay taxes but insult to injury the money is trapped for awhile not getting a return on it.

If a tenant were to get injured on the staircase, would I be liable for the injury?

If your tenant sues you for personal injuries due to mold exposure, your insurance carrier probably has a duty to defend you in the lawsuit.

If I were to include an addendum to the lease which states I am not liable for any issues pertaining to the storage sheds (whether they be to the sheds themselves or to the tenants from any injury), would that protect me?

Sounds like he gets wood from somewhere and splits and sells it at the property, and the fresh cut wood implies that it IS the current tenant.Personally, I wouldn't be too bothered by it, if I was able to verify that the operation was legal (no local ordinance prohibiting it, road side stand allowed, and here in Michigan we have bans against moving firewood due to the emerald ash borer, etc), that he was insured against injury, and that my own insurance didn't prohibit the activity.  

The injured persons personal injury lawyer will sue whatever they perceive as the deep pocket for that money such as the homeowner or investor.

Failure to do so could result in legal liability for any injuries or damages sustained by common usage of that easement.

Injury on the job is a workers comp case.

I also worry about my tenants' cars and of course the lingering spectre of a personal injury claim.I have not pursued a dialogue with their guardians because despite any diplomacy I may use, it will surely cause them to escalate.