Good. The first form, φανὲν , modifies φάος (to which it's related etymologically): "Ray of sun, of (all lights) before, the most beautiful light to have shone (literally, "having appeared") upon seven-gated Thebes..."
The second form, ἐφάνθης, is a direct address by the chorus to the sun: "You once shone (appeared), O eye of golden day, after rising over the streams of Dirce,...
Quite a task you've taken upon yourself! Anyone to help?