I have found a solution to installed fonts not showing in the pull down menu on writer.
I’m using LibOffice 220.127.116.11 on Mint 18.1 (64 bit) and was unable to have fonts installed in ~/.fonts show up on the pull down menu.
I downloaded and installed to /home/mydir/.fonts and /usr/share/fonts directories restarted LibOff and refreshed the font cache using sudo fc-cache -f -v but that didn’t work either.
I found that by logging out and then back into my account and starting Libre Office the fonts I installed in ~/.fonts would show up and be able to be used.
This is unacceptable behavior for any app in 2017.
Is there a bug filed for this?