PC is/was a big deal for the original Plants vs Zombies so I would imagine a Windows version is somewhere near the top of the list. And if everything MS has been saying about Windows 8 is true there's is a good possibility that W8/WP8/W8Surface versions would be only slight variations on each other and could/should be developed concurrently.
The official line at this point is something along the lines of "coming to other devices through the rest of this year and into the next."
What you have to keep in mind is the fact that just like the first game this one is gonna land on game consoles, Smart TVs, Nintendo 3DSs and imagine those are the devices that won't be seeing PvZ2 until 2014.
Will we get it before Android...I'm guessing no. The numbers are just too overwhelming. But I think we'll have it before year's end. It would be sweet to see it drop around Halloween!
I've never heard of any deals to launch games on an Mobile OS and keep it exclusive for X period of time (Ignore the Nokia stuff...that is exclusivity within Windows).
I know between, for example, between the Sony PS3 and XBOX 360 MS seems to have a real edge getting exclusive launch windows with Activision and Call Of Duty DLC.
Sony countered with perks and early access for Electronic Arts' Battlefield games & DLC.
You've really gotta wonder if Apple cut EA a big cheque to launch on iOS first, and have it only on iOS for 30 or 60 days. Think of the timing...new iPhone next month, maybe a new iPad too... PvZ2, only on iOS...that's some quality synergy. Maybe Google is shooting cannons of money at Instagram to keep off WP8 too.