Maybe. There are all kinds of thoughts etc on this. One of them is to create a virtual currency with an almost stable value that would reflect the resources of the brics and the national currencies will be compared with the virtual currency (instead of the dollar in the past). So maybe brics will make something. But i agree that the € is a failed experiment. Only countries with corripted governments would like to enter the €zone
Discussion
I've seen that idea of creating a common currency based on commodities and national currencies but I think it's infeasible. Would be way too complicated to set up and then maintain (against failure).
If a country ends up with an excess of a trading partners' currency then just exchange it for commodities they want to stockpile or for gold or eventually for Bitcoin.
Yes. But we will see that in the future anyway