You don’t have to clear as a family but you should declare as if a family, even when using separate lines to get to the baggage claim area — no less so if your belongings are co-mingled or may be considered to be co-mingled with that of the rest of the family members in the travel party.

I have seen 1, 2, and 3 work, but I have also witnessed CBP saying that it should be done differently next time.

At most airports of entry to/for the US and most of the times for some years now, yes. But sometimes it’s not been that way and gets changed from time to time at some airports of entry to/for the US.