According to our sources, AMD will produce just the 8 “Zen” Cores Die, at least initially. This strategy will save a lot of money, because AMD has just to design a single Die. From this single Die, AMD will be able to commercialize 8 cores and 6 cores Zen CPUs in the retail market (maybe, with and w/o HT enabled). Also, in case of bad yields, OEMs/ODMs can use 4 cores Zen CPUs. So, no dual core Zen CPUs.
AMD will commercialize Bristol Ridge APUs with 2 and 4 x64 cores as entry level CPUs. AMD want to attack Intel's leadership in High End CPU market, and to accomplish this goal have to launch a massive attack.