Lossless is lossless. You can verify that by converting back and forth between a losslessly compressed file and the original uncompressed WAV file. They should be bit identical. You can't do this a lossy compression format like MP3.
Picking a DAC for a music server is the same as picking a DAC in general. The only special consideration is whether you need the added convenience of a built-in USB interface which you may or may not need, depending on your set-up.
Picking a DAC for a music server is the same as picking a DAC in general. The only special consideration is whether you need the added convenience of a built-in USB interface which you may or may not need, depending on your set-up.