Might as well have it on XCP counterparty and MSC mastercoin as well as NXT AE so it's in all of the markets.
i dont think this would work, you can only make the asset once and cant add or remove assets from the total amount, so what do you do if you go 50 50 between two platforms but then you have 80 percent asking for nxt. Its not feasable to use multiple platforms for one asset.
They wouldn't be all released at the same time. Assets need to be able to be deposited (bailed in) into, and redeemed (bailed out), of any of the exchange platforms.