Wip does now own the rights to the Federal/Fluidyne skis. Depending upon which ski parts you need, they are the ones to contact, though Atlee Dodge and others also have some parts as well.
Can't help with the other question. There are so many ski designations, and so many of them simply mean a later model of the same ski, that i havent kept track.
I don't have my fancy sheet of Federal sizes with me, but if I recall correctly my 2000A's are an inch wider than 2000's and otherwise pretty much the same.