Another newer fan theory is that Gray Wing and Stormfur are somehow related.. I don't know why I came up with this, but I very much enjoy the idea of Gray Wing's kits somehow having a bloodline that leads to Willowpelt and Patchpelt, and thus Graystripe, his kits, and his grandkits. When I see Stormfur, I'm somehow reminded of Gray Wing for some odd reason...
I also joined the "Hollykit, Jaykit, and Lionkit are the kits of Crowfeather and Leafpool" club and have been calling that for a very long time. It was too easy to figure out.
I thought the EXACT same thing when I first DOTC, well, okay, not exactly. I too think Gray Wing is Stormfur's descendant, but rather, from Silverstream's side of the family instead of Graystripe's. I think one of Gray Wing's kits is Reedfeather's ancestor, Willowbreeze's WindClan father.
I heard about the Crowfeather and Leafpool theory from an Erin chat back when Outcast had just come out. When someone brought up the theory, Vicky replied in her usual wink, nudge, don't give a direct answer kind of way, but looking back on it, I can easily imagine her wondering, "Oh God, are we really that predictable?" I myself am kind of ashamed for not picking up on it before LS.