On second thought, you're right of course, the overhead for encrypting/decrypting X is pointless here. SSH X forwarding is bad.

It'll be one less thing to type, and one less miscellaneous script laying around, so I would have ssh set the DISPLAY variable for you, as I indicated. But on second thought: why are you using ssh anyway? Can't you just sudo debian epiphany? (Assuming you have all/nopasswd/all line in your sudoers.)