I can't speak about all the questions/details here but devkits have double memory amount than future retail hardware (is "usual" with the devkits because they need extra memory for debug purposes), the thing with this is that like memory amount is in an open range now (not closed) they have the "better" choice right now (I mean in the range the higher amount in the devkits). For example, if Wii U memory range is 4-5 gb, the kits have 10 gb instead 8 gb. So as I said before that memory can't be less than 1 gb, the kits have at least 2 gb
(is higher of course because this is the lower value of the range).
As far as I now, the amount of edram is specifically described in the video-graphics chapter not in the cpu one (there only speaks about L2 cache amounts for each core, is not the same for each one to be precise).
No specifics about any other types of memory (except for storage purposes).
But I have to check the latest info, not easy right now to get it (
), so take this as guiidance values (some of them won't change as edram, L2 cache or very unlikely to change, but others can change like the system ram that has to be set).