can an estate exist simultaneously with another estate in the same property
Hmmm.... I believe this would be a state law question which would require your county and state to really figure out. Are you referring to two buildings? An estate could mean a few things. Truthfully, as a rule of thumb: Whoever owns the property has the final say of what happens to what on their land. So it honestly sort of belongs to the property owner no matter what. This is why property lines are such a sore subject amongst neighbors sometimes.
It depends on the deeds really. If the property has 2 seperate deeds that puts the property together at sell than yes it can. But the one to answer this ? is the PVA office where the property is.