So emacsclient/emacs deamon work with a tty, basically emacsclient opens a tty and sends it to the emacs deamon and it uses it to send output/receive input, so you really need to be local there's no way that I know to forward a tty on the network.
So it seems possible with socat indeed, I'll have to give it a try :)
One problem that I see however is that emacsclient also forwards signals to emacs when the window changes size for example, I don't think that will work with socat
Almost all of Theia's features are based in the backend.
The emacs equivalent would be like having emacs in daemon mode and a tcp based emacsclient locally. (I wish that existed)
Also the idea is to have something a bit more modern and appealing to the mass of javascript/web devs out there.
Theia is still far from replacing emacs, but as an emacs user myself and a Theia dev I hope I can bring what I love about emacs to Theia :)