considering gnome runs on freebsd, that's just not true. The only work those folks had to put in was implementing one interface for what logind provides
Is gnome feature complete on freebsd? The article mentions gnome clocks wants to use timer units in the future, and gnome-session logs to journald.
As far as i know it is. As far as what's in the future no idea. I'm only speaking of the present.
Not really, it's garbage to the point that it only runs the X11 session, mutter can't even be compiled with Wayland support because it then tries to include some Linux-only header.
Eh, I'd say it's more likely pressure from RedHat. They benefit hugely from a complex ecosystem that creates demand for their consulting business.