The way I understand it, once Italy is complete, FMG will put up an order form which will be for a complete set of the AA50 six nations (Italy, Germany, Japan, USA, UK and Russia). When you place your order, you will get the Italians right away and get each other nation as they come out. Plus, with the other five nations, the wait won’t be as long because the factory will be more experienced at making the molds and putting out the product.
As for the other extra stuff like France, ANZAC, China and the common pieces, I think they will be offered later as add-ons.