This I do know. It's slightly doable. I think the major problem of the Celtic kingdom of Tylis is that not many Celts in the long run settled down in Thrace compared to the sheer numbers who migrated into Asia Minor and become the ancestors of the Galatians. You would need to eliminate Nicomedes I of Bithynia. He is the one that invited over the remaining Celts that had settled in Thrace to help him defeat his brother Zipoetes II and on a lesser note the Seleucid monarch Antiochus I who threatened invasion. Have Zipoetes defeat Nicomedes before he could make that plea.
Leonnorius and Lutarius would had continued their siege of Byzantium and likely conquered the Greek colony, establishing themselves as their rulers though they would had served as rivals to Comontorios who established himself in Thrace. Knowing how bloody and vicious Celtic politics is, it was either going to be Leonnorius, Lutarius or Comontorios who was going to end up on top when it came to ruling Thrace. It's certainly interesting.