In California, a tenancy in common is presumed, absent language to the contrary.Joint TenantsLike tenants in common, joint tenants have the right to possess the entire property.

She could sue you and get a lot of your money.You need to get legal possession of your unit. 

He also willingly left them in your possession which would make for a civil case not criminal.  

All I owe the tenant is possession of the property and to maintain it for the term of the lease.

Idk about driving it as much but it will be in my possession.

Plus he has the full contract amount in his possession because ''he cut us a deal if we paid up front in full.''  

Rent payment must be in the landlords possession,' in what ever form is agreed to, by midnight the day it is due, Not postmarked, not being processed, it must be accessible to the landlord the day it is due.

This was the explosion referenced by Bill I was referring to (and I've on various occasions seen these on the local news):While I certainly cannot say with absolute certainty that a water heater failure as you linked to and was demonstrated in your mythbusters video, could not cause secondary damage, for instance by severing the NG line feeding it (as it would likely do this) - the primary failure and explosion demonstrated in the video due to the T&P relief failure would not possess the energy / mass to produce the damage that Bill was referencing above.   

This would also suggest that massachusetts is a title theory state because legal title is held by a trustee not the "owner" aka person in possession of the property.

Agree.If there is damage by a tenant (smoking, candle wax, crayon, etc), it's on them, but normally it is wear and tear for the landlord to cover.The first thing we do when we take possession of a unit is assess whether painting is needed, and full or partial.