To the Estate of xxxxxxx
You would address it to the last known address with "The Estate of xxxxx" on the first line. Or check the notices for the address of the lawyer handling the estate.
You can't, an IP address is not fixed.
A persons estate is all the property they own both real and personal property.
The web address of the Glensheen-Historic Estate is: https://glensheen.wp.d.umn.edu
The web address of the Ashland Henry Clay Estate is: http://www.henryclay.org
There is no set time limit, it would depend how professional or knowledgeable the persons or persons dealing with the estate are.
I
It's a Japenese warrior who vows to protect a rich persons estate
Yes, you can waive inheritance. Typically there is no reason to do that.
The persons address and there name
Yes, In most countries the law would require that the life insurance be paid into the dead persons estate - if the dead person owed any debts (to tradesmen, banks or for government tax) then the estate must settle these before the dead persons relatives can inherit from the estate.
Yes, the government can do that. The value of the benefits is part of the estate. The assets of the estate have to be used to clear all debts before anything can be distributed.