Personally I think you should continue with your NAS, it adds a bit of complexity to your setup but the BDP is no longer dealing with the file system storing the audio files and network traffic has less overhead and in addition a synology has some great software / ecosystem for doing things like creating backups. There no software issue that will prevent a BDP from reading an SSD larger then 2TB, but you will need to format the drive before installing it because Manic Moose doesn't support creating GPT partition tables.
Chris