I want to ask something about your townies' issue.
About the university student, do you have Get Famous EP in this saved file? If you have GF, the game prefers to use existing unemployed household members to be university students (and organizations) instead of creating new ones every time. However, there are some conditions. They have to be in "Other households" (Not my household or played household).
About the dorm roommate, sadly the game will ALWAYS make the new ones to fill the bed in your dorm. If you have 10, then there are 9 roommates. (I am not sure about the maximum)
Many more roles will make the game create new townies. So 100+ may be from other cases.
Oh, did you use the "Home Region" mod? This mod will make the game need to create townies for each world. For example, the vendor NPCs will only work in their hometown. So, if you visit 10 worlds, you may have 20+ vendors.