Heh. But transcoding WMA to FLAC to WAV would be rather overkill if you ask me. But if what you say is correct, it is possible.
The WMAL to FLAC conversion is a one time process. You can delete the WMAL files when done.
The trigger point in a SoundBridge for having WMA transcoded to WAV is 400bps and as Fizze already pointed out, the SB can’t play WMAL.