I found some of the pyramid parts in Castaway Stories. All of the new pieces except one copy of the open door are decor and found under "rocks" as that is where the original parts are found.
There are two versions of the open door, the decor version and the wedding arch version.
The decor version of the open door has it's footprint back and off to the side so that move objects won't need to be used to place it.
The wedding arch version of the open door has it's footprint just inside the door so that hopefully the couple can be photographed through the doorway.
I did a test wedding , the doors do not block the view of the ceremony but some of the guests stood in the wall:
The steps are slightly darker than the rest of the set for some reason. (Probably my own error.)
The sims cannot pass through the closed doors. They are decor only.
I used the automatic footprint tool to improve the footprints of all pieces but the arch. I left the arch with the *way too small* footprint so that Sims can pass through it. I also changed the pieces to only have the high LOD meshes because in my opinion there was too much distortion when backing away. *Please forgive the Hag she knows not what she does!*
You still need to use "Move Objects to place most of the pieces as the auto footprints don't allow the parts to be placed close enough together.