Without an explicit execution-order rule, what can component A safely assume about compon…

Without an explicit execution-order rule, what can component A safely assume about component B on another GameObject during A.Awake?

1. Nothing about whether B.Awake has already run
2. B.Awake has run if B is higher in the Hierarchy
3. B.Start has completed before any Awake call
4. B is ready whenever both scripts have order zero