We are only ambiguous with our answers so as to not promise anything we can't do towards the end of development.
As far as development goes for now, MSFS is more limited in terms of it's SDK compared to it's P3D counterpart, however when programming externally the possibilities are opened a lot further. One major component to that is the MSFS marketplace, as they do not allow externals to be used in any marketplace product, so until that changes, we may not sell the product on the marketplace so that we are not limited to the SDK only.
I cannot directly say if the weather radar has already been implemented, but what I can say is that yes, MSFS's weather radar capabilities are little too limited to be useful enough for us to create an accurate depiction (as is probably well known by now). And there really isn't any weather API (at least not in the traditional sense) however a dedicated weather API is scheduled to be implemented during this year; no specifics were given and we'll just have to see if it comes out before we finish the MD-11.