I don’t think that is possible. For a music playback lock screen widget to be available, it has to be able to pump its output through the Apple Music framework, since that is the only music framework that is guaranteed to be allowed to remain operating while in the background (and, therefore, work reliably as a widget on the lock screen). The Lightning DS software is not playback software wherein music comes to the device to be played; it’s merely a remote control for your Auralic device(s). (As I am sure we all know, the Auralic software does not reliably operate in the background; that is why it takes a moment to resynchronize when you come back to it after you go to another app).
An example of third party software that I have that relies on the Apple Music framework would be Synology’s DS Audio app. So long as my output device is set to my phone or iPad (or a bluetooth device that is set to receive music through the phone), I can see a lock screen widget for what is playing. (If I remove the AppleMusic app from my phone, however, there is no lock screen widget available). But if the source I am controlling with DS Audio is something other than my phone (say, an AirPlay device), there is no lock screen widget available.