I've been playing with meetme2theriver's clean Pleasantview neighbourhood template and their Strangetown shopping district subhood. I mistakenly added the EAxis Sim State University and only after adding it did I realise it wasn't the clean template. I want to add meetme2theriver's clean Sim State University template and delete the EAxis one, but I'm not sure if removing it would be completely safe. I have never played in the EAxis uni in this hood, I loaded up a dormitory lot in build/buy mode but that was it. I didn't save the lot either. I do have a backup from 2 days ago but I'd rather not use it if possible because I've made a lot of progress since then. Thanks!

There is a point that you cannot delete sims shipped with university and they will stay in your hood even if you delete uni hood itself. Replacing hood is possible but I'd rather go with Jawusa's clean and empty SSU in this situation because if you add inhabited uni it will add students as well. Rename existing Maxis SSU in your hood with something else, install Jawusa's SSU in program files and then add it to hood. After that you can delete old SSU without problems, all playable students will appear in new uni bin.
If you don't want students, dormies and other NPC from Maxis uni, easiest will be revert to backup, other way is to kill them all, move graves somewhere in main hood and delete SSU.

I've just added Jawusa's SSU and it's working great, thanks so much!

So I've just run the hood through hood checker and got these under Memories:
Lot does not exist: 0x02A8 Ashley Pitts: [Invisible] Member of Greek House: 0x0038
Lot does not exist: 0x02A9 Joshua Ruben: [Invisible] Member of Greek House: 0x0038
Lot does not exist: 0x02AA Kevin Beare: [Invisible] Member of Greek House: 0x0038
Lot does not exist: 0x02AB Castor Nova: [Invisible] Member of Greek House: 0x0038
Lot does not exist: 0x02AC Tiffany Sampson: [Invisible] Member of Greek House: 0x003A
Lot does not exist: 0x02AD Brittany Upsnott: [Invisible] Member of Greek House: 0x003A
Lot does not exist: 0x02AE Heather Huffington: [Invisible] Member of Greek House: 0x003A
The hood checker couldn't remove them. Are they a problem or shall I just ignore them?

Yeah, delete them. Heather, Ashley, etc. are still in the neighborhood, but the Greek lots they're marked as members of are gone. If it bugs you, you can use SimPE to remove the tokens, but I wouldn't bother, myself - messing around in memories in SimPE is tedious, and these tokens aren't hurting anything.

That's good to hear, I think I'll just leave them then. Thanks!