In the case that a UM toon dies, a character res can be used so long as the character hasnt been dead for over a year.
Are we sure the name would become available? or would it be held with the dead UM for a year?
If you die and res up and you end up at character screen, the name will be readily available. If you choose to character res the UM that you sacrificed, it would probably have a number at the end of it's name when GM resurrected.
Name (main toon)
Name-1 (GM Resurrected toon)