The Solas romance is the emotional equivalent of him sweeping you off your feet and dumping you into a pond only to throw himself into a different pond a few feet away.
Incidentally, the big reason "I Am The One" doesn't translate is because we didn't write it. "Leliana's Song", in contrast, we did. Either way, you are correct that Elvehn is a cipher. We keep it simple so we can all use it, and I've no doubt that makes it look pretty silly to anyone with linguistics knowledge. I like your posts on the subject, rather a lot.