It says in the link description you posted, H mode only and can be adjusted in game options/plugins.
Having multiple versions at the same time won't fix it, as sideloader only runs the latest mod version and ignores the rest.
If it's character related, place the mod one by one and check which version was used, then copy those settings and apply with the latest version installed.
Use the mouse wheel click while in free roam and open the clipboard, you'll see either one of the 4 scenario girls at the top of the roster (a star floating symbol will appear on the map), or a teacher, during each of the periods.
For the girls, just interact with them when they appear. For the teachers, increase the 3 MC's stats, recruit girls to your club and have H with them and then go talk to the teachers. You'll get two cutscenes for each after a while, the second one starting and unlocking H scenes with them.
As far as I know that DLC is party exclusive, it adds to it the rest of the content you have already in the current repacks (JP) like clothing, dates, personalities etc.
