Is only a gtk application for configuration and a status icon.
Its nice for some - but not required if you are going to manually configure the printer as you do in the final steps.
sudo
is not required here.
You should enable the socket only.
avahi
is a dependency of of cups
which is a dependency of manjaro-printer
.
Correct.
Revised steps (also using pacman because it is more reliable);
sudo pacman -Syu manjaro-printer system-config-printer
systemctl enable --now cups.socket
systemctl enable --now avahi-daemon.service
lpadmin -p $PRINTER_NAME -E -v ipp://$PRINTER_IP_ADDRESS/ipp/print -m everywhere