No, this is a good thread.
I agree with
@Mystic Mistral on this one.
I read all chapts of Fairy Tail Ice Trail (obviously), and although it is true Gildartz is stronger than Ur, he probably isn't too much stronger.
Besides, Gray and Ur sharing the same type of magic and having close relations could allow them to perform a Unison Raid, which I think would be enough to oneshot either Gildartz or Natsu.
Gildartz and Natsu would also have to be on high alert, cuz with 2 ice make mages, there could literally be infinite clones waiting around to fool you.
One last thing, you guys are missing one thing.
Gray is IDeS, perfect for forming a duo with Ur. Ur can feed him as much of her ice as she wants.
It probably tastes good too.
Given that Gray can be refueled constantly as an IDeS:
Gray and Ur win high diff if they are lucky and extreme diff at most.
Never underestimate the lineage of the Ice mages. Just cuz the thread seems obvious doesn't mean it is. The Ice Mage Lineage has powerful users in their ranks. Be careful.