I don't have personal experience with it but the only FOSS desktop publisher I am aware of (as opposed to illustration or word processor programs) is Scribus.
It is comparatively lacking in features and less user-friendly but could still meet your needs. It definitely works on Linux, whereas the Affinity Suite is not officially on Linux and it can be hard to get it working there.
I have used FontForge in the past, but never to create a font...