I'm sorry. I just read about 12 of these pages in a row and was shaking my head so hard at the end that it almost came off. IMO, Alleras=Aegon is a huge stretch, and so unlikely it's odd that it has been discussed for so long. (please don't take offense, I'm just not convinced)
Alleras has to be Sarella. I'm very sorry that I don't have direct quotes to back myself up on this, but Young stormlord has done a good enough job defending my position that I don't really need to.
My thinking, however unimportant, is this:
The mirrored name? It cannot be dismissed as too easy- I didn't see it until it was pointed out here, and it seems a bit too much of a coincidence to mean nothing.
A girl can disguise herself as a guy. It has happened before (there was a few in the civil war, i know that) and described as he was, Alleras is a fine candidate for such a secret. Plus, come on, people- hasn't anyone here watched profound classics like She's the Man or Mulan???
Another thing- we still have no substantial proof that Aegon is alive. If Aegon=Sarella, Arienne wouldn't have thought of him? as her sister- and I would think it would be much harder for a guy to be disguised as a girl than the other way around
IMO, there would be more clues to all of this at this point in the story. The sphinx things are clues to Alleras=Sarella, I didn't get any Aegon vibes from any of that.
So thats my two cents, or possibly five dollars worth. Take it or ignore it.