Example unity has this as the execution order : Unity - Manual: Order of execution for event functions
What is it for unreal ?
Have you read this? It might not be a complete answer to your question but I guess it helps.
Also you have some functions that says itself like beginPlay(), Tick(), EndPlay() etc…
And the level blueprint most likely spawns before other blueprints, but that’s just my guess.
I asked this question to make the effective initialization of run time variables by knowing the loop you know how to handle the init time of specific variables and not letting them to spike .