Has anyone figured anything more out?
No matter what I do, if it gets sent to my apple id email, I receive it only on my iPad. If it gets sent to my phone number I only receive it on my iPhone.
I remember at least on iOS 5 I received on both when sent to email.
Edit: Ook so got mine to work now. I followed swordfish's advice in turning iMessage on first on the iPhone then the iPad afterwards. The iPhone didn't activate at first but apparently because I was on wifi and it has to be on cellular for some reason. Afterwards I had to wait 20-30 min for it to start working correctly.