Regarding the exclusivity, a Popcap representative had this to say:
I will keep putting this info out there today but I want the community to know, we are only exclusive to Apple first. We have plenty more info to hand out just not quite yet. When I have more news to share, I will indeed. And we are reading your comments and understand your concerns. That’s why I keep trying to post replies in here so you all know what’s up!
So it seems that the word “exclusive” actually means first to launch and that it should be available on other devices (Mac, PC, Android) after a period of time.