Awesome!! Thanks so much
@trinidad and
@firenice03 .
I did what Trinidad said, and it worked 100%
I put the TrueType fonts into /usr/share/fonts/truetype/ as admin user (I did this via file manager GUI under "open as administrator" via drag-and-drop, and... it worked! My other users could access them on their system and in LibreOffice! Thanks, Trinidad.
I had one font that was .otf format only, which was opentype, so I put that one into /usr/share/fonts/opentype/ and it worked too, the other users could get them on the system and in LibreOffice.
Trinidad's method also turned out to be a lot faster when dealing with 8 fonts at once (which I was), than opening up each font and pressing "install".
Thanks also for the input Firenice, I had no idea about Lite Fonts and was glad to hear about them. The fonts I am installing are not related to those, but it's still good to know. Thanks for taking the time to help.
Wow! My family and I are thrilled with the ability to access these new fonts! Thanks everyone.