Apparently Shift Up is currently testing a new tribe tower that will reset periodically with 50 floors only for Elysion, Missilis and Tetra, not Pilgrim.
You can get 2 guaranteed SSR molds of each manufacturer after clearing all of it, but not all Nikkes are included in the mold only a select few Nikkes can be obtained through it, you can see the list in picrel
https://arca.live/b/nikketgv/144812942