Here's the exact way I ended up doing it.

I did install that when following your instructions as that wasn't there, but it didn't change the status.

Still didn't work for me.

I contacted Brother for some ideas on building from source with the deb files. No luck:

Is there anything I can do to help test this script? I think I followed that process that @der_eismann stated.

I'm not technically savvy enough to understand the full implications of that, but if it is the most portable and easiest method, that'd probably be best for multiple applications too, right?

In T4926#88006, @der_eismann wrote:

I was thinking about writing an installer for Solus, but it's not that easy. Either we use .rpm or .deb files and just unpack them, which would be easy, or compile them, since they also offer the sources on their website. But for that one you have to start some good crawling of the Brother website and the downloaded archives because they are packed differently with each revision... I don't know.