It depends on what jurisdiction you are in. In many jurisdictions, police are legally permitted to enter a premises whenever they have "probable cause" or "reasonable cause" to suspect that there is an illegal activity in progress (for example, if they could hear someone being attacked). Some laws also may allow police to enter a house without a warrant if they are in the course of investigating a specific crime.
No
Yes. The police can search any items if they have a warrant. It does not matter that no one is there to receive the warrant. The police only have to leave a copy of the warrant at the residence.
only if they have a warrant.
Technically they cant unless they have a search warrant not an arrest warrant.
10 days from the issuance of the warrant.
Then the warrant is no good and any evidence obtained would be inadmissible.
Yes.
Yes, you are not necessarily required to be present.
If it is a felony warrant yes they will arrest you
No. They have to have a warrant for each living space.
With a Warrant, consent, or exigent circumstances
Yes.