I was made aware, not that long ago, that the night to day transition is just there, no particular purpose, or at least I don't remember
To get the scenes you want there are few prerequisites:
- rel 100 (just as you wrote)
- have seen all previous event scenes (rel 20 cooking, rel40 running duo, rel 60 couch tit grope, rel80 running bathroom bj)
- once the above is checked, you simply start the night and the game should automatically trigger the rel 100 cutscene