1) We have all said things that we regret. We still regret the things we have said?-- No. It says that this happens generally to all of us.
2) We have all said things that we later regretted. We regretted the things we'd said, but it's unclear whether we still regret them?-- No. It says that this happens generally to all of us.
I retract my original statements, because I think they were misleading. In your first post, my comment for #1 remains the same, but sentences #2 and #3 do refer to the past and have the same meaning; it is merely the intent that applies generally to any time.
As for your more recent post:
1) I have said a number of things in my life that I regret. I regret a number of things