7 seems to be associated with temples in the ancient near east. Baal’s temple was built in 7 days and Enuma Elish (a Babylonian temple text) was presumably read during the 7 day New Year festival. There is a 7 stage structure to the building of the tabernacle in Exodus. Interestingly, I think Genesis 1 is a critique against the temple system as it existed under the monarchy (and the monarchy in general) and thus features a similar 7-fold structure.
The 7 resurrections strikes me as “theologian math” as one is unique to Luke and one unique to John, though I can definitely see John throwing it in with the express purpose of lining up the numbers.
And yes, you can go to the Norse for nines and further East for threes and fours. And probably elsewhere for the rest, but it is all very interesting to be sure. I think the running theory on why sevens were significant was the ancient fascination with the seven celestial bodies (the ones visible to the unaided eye) that move through our sky.
