blend should be very easy, though i guess not that easy unless you're lucky. i knew a place in boston that had it up until maybe 5~6 months ago, and i'd have traded it for a local seasonal. haven't seen any recently, but i'd be shocked if it's not on the shelf (or in the back) somewhere in america.
the blended version of papier shouldnt be too hard its the barrel aged versions that are gonna be a pain to find, especially the brandy and rye whiskey versions
set yourself up with a consistent Cali trader and its very easy. If you havent, follow the advice given above.
The regular Coton was easy to get until recently. Now its about two years removed from being a 'shelf beer'. Shouldn't be too hard if you find someone with a stockpile of the stuff. But for people like me who only have one or two bottles, it will take a little more. Nothing crazy though. Maybe a limited Upright release?
Coton (not barrel aged) was on the shelves at Provisions about 2 weeks ago, might be somewhat easier to get now