Does translation affect number crunch?

I think this is a no. Number crunch applies at the start of battle, starts gained through further buffs should not apply to this.

Pretty sure that's a solid no. Any uniques/leader abilities should be passed through Number Crunch, but not from buffs. I don't think there's an exception because he starts with Translation, as it is still a removable buff.

You could always test in GW by running the same node with 3PO or another Rebel. Use a group heal that bases on the own character's max health and see what the numbers say.