Second vs Third conditional

If I had known the answer, I (could/had) have said it to you.

You wouldn't go to a party (nevertheless/unless) there were a lot of your friends there.

If we had grown up in a different place, we (would not/must not have) become who we are now.

If we had had different parents, we (would have / would had) developed different personalities.

If you helped, you (might/instead) get their gratitude.