Yes, you can waive inheritance. Typically there is no reason to do that.
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.
The estate is responsible.
The estate has to pay the bills. Which will affect how much the spouse can inherit.
you have to prepare an invoice that needs to be presented to the executor of the dead persons estate.
Yes, you are responsible for them through the estate. They have to be cleared before the spouse can inherit anything.
The estate will be responsible for the bills. The spouse indirectly will pay, as they cannot inherit until they are resolved.
A deed to a property specifies who owns the property. If the property belonged to someone who has died then the property (and the deed to it) become part of the dead persons estate. What happens to the estate is determined by the dead persons will. In view of this it is unclear what you mean by a property deed overriding a will - your question makes little sense.
The "estate" is everything belonging to the dead person. It is calculated by subtracting everything owed from everything owned. In other words it is what is left after all the dead persons debts and funeral expenses are payed but before any death taxes are calculated.
The spouse is not personally responsible for the medical bills, unless they co-signed them. However, the estate is responsible. Which means that the estate may be depleted, and the spouse might not inherit anything.
A will is a document that directs how a persons "estate" (that is all their possessions after all debts and taxes have been paid off) is to be disposed of after they are dead. The will may or may not leave some or all of the estate to the persons children - also the laws in some countries my override the provisions of a will in certain circumstances.
The spouse is not personally responsible for the medical bills, unless they co-signed them. However, the estate is responsible. Which means that the estate may be depleted and a lien placed on the house. The spouse may not inherit anything.
The spouse is not directly responsible, unless they have co-signed for the services. The estate is responsible for settling all medical bills in Oregon. So before the spouse can inherit anything, the estate has to pay the bills.