As for 1) There does seem to be a sign where I remember it. The path to the north is not official and it leads straight though a closed off area. I will set it to access=no. Aerial imagery does not suggest the path is used much. It may be a case of "it's possible to walk there" but with a lack of tracks. Thus, I will set it to trail_visibility=no as well. If there is no usage of the path, I would also vote for deleting it.

2) is still open, i.e., whether Mesa Point Trail is closed.