First, to clarify: you want github.com/FortAwesome/Font-Awesome and github.com/twbs/icons to be modules, correct?
If that is your intent you need to actually fork the repos and make them hugo modules.
hugo mod init and any
config.toml (or equivalent).
AFAIK pulling in a non-module repo as a module won’t work, at least not with hand-coded ‘mounts’. It might work in a ‘pure import’ scenario, but I’m not sure.
I’ve run into this myself where I tried to import non-module and it just did not work.
I’ll see about a full demo soon.
I’m remembering now that I’m working on it, is that part of the issue is that go modules have specific expectations about versioning (tags). Will post more later.
Also, because you have an ‘assets’ source mount you won’t see sources below ‘assets’, IIRC, within that repo. (with
hugo config mounts). Order may matter.