[Zubersoft]

1) Yes, MobileSheets for Windows 10 is a separate application that is sold on a separate app store (the Windows store).
2) You can certainly be a part of the beta. I'm either going to just post the link to the private app store listing so anyone can join the beta, or I'll email out the link. I can't think of any reason not to just post the link here though and let anyone join the beta that is interested. Having a separate beta version for Android turned out to be quite a pain for a number of reasons, so I'm hoping this approach will be better, as the beta is just an early release of the same product that will be sold when I'm ready to make it publicly accessible.