You can go into the save.json file of your game in your C :\ Users\(Your User)\AppData\LocalLow\Glitch Pitch\Idol Manager\data
Then look into either the story mode folder if you're playing story mode, or if freeplay in manual saves.
Scroll down in the file until you find their names with their stats and stuff, you can alter the speeds at which they gain them or alter them completely to higher numbers.

Make sure to save that and then also apply the same to the autosave or else your manual save will disappear from the game.

And for graduation, depends what you want, but if it's to stop them graduating, here's the mod for it
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2977892324