Majora's Mask is not going to happen.
They've said numerous times (Miyamoto, Aonuma and probably Iwata himself too) that they will release an original Zelda before they start to think about any more remakes. Though I still think Zelda will release this year, I don't expect it to be announced in a couple of hours.
Of course, I'd love to be proven wrong !
Secondly, making Majora's Mask will take away from their 'developing power'. The main team is deep into development of both the original WiiU Zelda and the Wind Waker HD remake. So they have their hands full. This means that it is highly likely that the original 3DS game will be developed mainly by GREZZO with oversight by Nintendo. Like Capcom did the Oracle games when the main Zelda team was busy with developing Wind Waker. They don't have time to do a Majora's Mask remake too.
Still, I'd love to be proven wrong on this also !
Lastly, I'm looking forward to it. Less than three hours left!