A .deb relies on other packages, so a modern Firefox package will not be installable on an ancient OS. With Ubuntu Pro, Ubuntu 16.04 will still get updates until 2026, so I think you would get Firefox from Ubuntu until then. But there's no chance you would get a modern Firefox for 7.10 or 8.04.
Maybe you should ask yourself why you would like to cling to an ancient version of Linux. You don't like the new desktop or anything else that comes with the new version? Then you can install another desktop or another distribution.
Ich vermute, dass das "drahtlose Steuersystem" die Info über den bestehenden Netzanschluss bekommt, nicht über Funk.