Yeah that's pretty gray indeed.
What's the incentive for Tom to defend the interim title (outside of obviously getting paid).
He could lose, then he's never was the real champ and if he wins, it still means nothing because he has to fight again.
I really hope UFC is putting a timeline on this stuff.
After the Jones/Miocic fight, the winner should have 30 or 60 days to sign a new fight or vacate given the circumstances.
In this scenario where both guys are potentially retiring after the fight (or at least the winner might), it might be a benefit to tell Tom that if he defends the interim belt successfully, he would be guaranteed the winner of Jones/Stipe OR be named the undisputed when the winner of Jones/Stipe declines to fight Tom to unify the belt.
Clear as mud.