Particularly at google for director level roles.
Once you get the offer and signed, yes, you should let them know
I agree. Wait until at least they extend an offer.
After everything is signed. Too much discrimination.
Wait for the offer and then definitely let them know. It happens quite often as people of course already have plans for the next couple of months. So don't worry about it but disclose after you sign.
Can you delay start date to after?
I’d rather not. Thats a long time to wait in no mans land. Plus Rokus family leave is not great.