Where would I be able to find the packages I'm looking for??
Inside the PPA
Everything I find tells me to use the PPA, which isn't possible for me atm since I don't yet have internet
Well you do need internet to download anything ...
So I need to download the packages/dependencies and transfer them to my PC to install them...
and this rooted phone can't teather or hotspot including through ADB.
That is weird: using a phone as a hotspot is always possible. It is a core feature of modern phones. Does not require a rooted phone either.
I would use a live usb session to create a Linux system. Use that to boot from it on a system that has internet, then download and install Nemo FM and then copy the files from /var/cache/apt/archives/
to your other system.