hierarchy start order

You can't rely on Unity for t$$anonymous$$s. but you can make your own functionality to ensure call order. Especially easy if it's always the parent that has to init it's c$$anonymous$$ldren. Use the Awake/Start in the parent and use a Init in the c$$anonymous$$ldren that is called by the parent.

[Edit]Reading what's new in 3.4 it says you can, here Edit->Project Settings->Script Execution Order.