The very last page of last issue..
"You're better off without him."
[ and some say there are two. ]
- Immortal Hulk #11
This issue has a lot of talk about twins/pairings. Then on the page talking about Angra Mainyu and twins.. there's two cribs. Most of the B&W pages on this page seem aimed at Banner except the last two. Throw off the scent perhaps? There's been a lot of subtle hints like this over the issues.
"First born"
Even more double speak -- the next page Brian didn't want "children".. innocent or hiding in plain sight?
Rebecca had a rough birth that almost killed her. Brian wasn't in the room. There's potential for a twin to have "died". This also plays into the idea of Bruce saying he was "already dead".. if he died at birth and was brought back (and he has that 3rd form of gamma) then that's the start of the resurrection stuff.
Also, Bruce had twins with Caiera as well. There's a greater chance of having twins if you're a twin. It'd explain why Bruce is seemingly in two places at once.
Maybe the third form being referred to is the merging of these two sons into a third.