Q#1: Van's RV-12 prototype #2 is still registered as R&D.
There must be a version of the RV-12 registered and certificated as a "Special Light-sport" before anything can be done towards an "Experimental Light-sport kit". I'm sure that they are working in that direction, but those things don't happen overnight. It will probably be some time before the kit will be an official "ELSA Kit".
Q#2: A lot of airplanes have been flying a long time built with these rivets. This is of a very minor concern.