What is the best add-in or App for what i need (Microsoft 365)

Hello community, 

I am currently working within Microsoft 365 (right now mostly just using teams, one drive, outlook, and occassionally sharepoint). I am trying to move over an onbaording system that I created into one of the apps or add-ins, but i am not sure which would be best for what I need. I am hoping to keep it simple, as some add ins i already tried to download (like the sharepoint: sapients employee training management add-in) would require approval for our whole university, which likely wont happen. I am hoping to keep it to one of the more common apps that might already be approved.  any help is appreciated!

I am managing all of the checklists and tasks that new staff need to get throguh when they onboard with us. The onboarding documents previously lived in a shared file folder drive, and what was nice about that was that within a word document, i could embed a link to any other saved document on the shared drive.  This navigation was helpful, as users didnt need to know what folders files were in, they just had a direct link to open up a specific document from the one that they were in. A common new hire guidebook would link to multiple checklists needed. 

It would also be helpful to be able to have 1 team, but with chanels that are set privately so that when we hire a new staff I can coordinate with them and them only. Ideally, they wouldnt be able to see the progress their peers are making, and each peer would get their own "channel."

If anything has functioning to set reminders about tasks that need to be complete, or has a way to alert me as an administrator if tasks are not completed, that would be awesome too.

I am sorry if this question is not appropriate to ask here. Please let me know if there is a better place to inquire and get guidance. Thank you in advance!