There is no 'statute of limitations' regarding property. It sounds like a life estate that will revert to the estate. You should consult an attorney in your state for specifics.
aquire property
NO
If a person on social security disability inherited a property and then "deeded" it to a person who is underage there is one property. Why do you think there are two?
That would mean a property owner who acquired their interest in the property by virtue of a deed.
A deeded piece of land is a property that has been signed over to you. It could either have been paid for or given to you as a gift.
If they deeded the property to anyone during their lifetime it belongs to that person & won't be included in the probate, unless the property was part of a family trust, or some other arrangement.
you might want to sell it as fast as possible
It depends on how the property is deeded.
No, the mortgage is a debt of the estate. That mortgage must be resolved before the property can be transferred.
True
the state
If you mean the parents have deeded or willed the property to the person who will become the executrix, then, yes it is legal and not unusual, absent evidence of wrongful persuasion or the like.