I'm not sure Bekele has enough time to become the marathon GOAT. The minimum requirements you laid out are definitely good, but even if he meets them I still might give Kipchoge the edge due to his incredible win streak + his run in Monza that opened the floodgates to the crazy sub 2:03 clockings we've started seeing. Bekele would have to take gold in Tokyo and demolish Kipchoge's current record for me to entertain the possibility of him being the marathon GOAT.
I would have liked to see Bekele take the record today, because I suspect Kipchoge will lower it again after he crushes the 2 hour mark in Vienna. In any case, the marathon just got a lot more exciting. Let's hope Bekele can stay healthy. He looked phenomenal today.