OK so I solved it myself. For other Fedora users here is how you do it:
1.sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-27.noarch.rpm
2. sudo dnf builddep mpv
3. git clone https://github.com/mpv-player/mpv
4. cd mpv
5. ./bootstrap.py
6. ./waf configure --enable-vapoursynth
7. ./waf
8. ./ waf install
9. mpv
If mpv gives an error after you type in mpv, then do this:
10. which mpv
11.ldd /path/to/mpv/
12. cp /path/to/dependency/ /lib64/
I hope this helps someone.
EDIT: By the way, I never did fix that VLC error, so there is still room to work in this thread.