For whatever reason, Audacity's bit-depth and resampling options are severely lacking (or missing). I've been using
Wavosaur for quick-and-dirty editing of that sort, since those are basic tasks. You may want to use a
dither plug-in when you change the bit-rate, but realistically it's not essential.
Decode the FLACs
Load a WAV file
Process -> Resample, 44,100 Hz, OK
Process -> Bit depth converter, 16 bits, OK
Done!