Bummer!
The sprites from the X/Y project aren't so many so that isn't so bad.
For the GWSC, it would be great if you could recreate it, but it would probably be difficult (since you have no reference) and will take a lot of time (since you won 9 times ^^).
I'll hear around first if there is a way to get them back (maybe a computerwhiz knows how to do it). If that doesn't work, we'll see what is possible to redo.