Damage to someones property if you were at fault.
you can leave flowers
It depends. If you are on public property you may be within your rights, however, at some point it may amount to loitering. On the other hand, if you are on private property without the permission of the owner you are trespassing. If you have not been previously warned, the police will issue you a trespass warning and order you to leave. If you have been previouslywarned, whether by letter or a "No Trespassing" sign, you are subject to arrest.
yes
Their actions and reactions to outside stimuli.
Yes
Not unless they also have an interest in the property other than a tenancy by the entirety.
leave, i leave it outside
Search warrants.
You could be arrested and fined or put in jail. You will also have to pay for the damage to their property.
No. You need to seek permission from the owner.
This can be possible when the property taxes are not paid by the owners and the taxing authorities seize the property and sell it at auction to collect the past due property taxes.