No, I think it's Allshare that's the Samsung DLNA equivalent. Allplay is the open-standard network sync protocol from Qualcomm. There are a lot of these protocols now e.g. Denon, LG, Yamaha, Pioneer, to compete with Sonos, but Allplay is the only open non-proprietary one and has been adopted by multiple manufacturers. The SDK is freely available to incorporate into products and software so that they can play to Allplay devices.
The Panasonic device listed above is both a DLNA renderer and an Allplay receiver, so you can either play to it using DLNA or Allplay. (Think of it as like Apple Airplay, with the advantage that it's an open protocol and you can send independant audio to different places). In the MC scenario that doesn't yet have Allplay protocol, you could send to it as a DLNA renderer but then link together several receivers/speakers via the Allplay protocol using a generic Allplay app (similar to a generic DLNA controller). Like Sonos, Casatunes, and all other multiroom systems, grouping and controlling rooms is simple via an app (see attached pic).
The point here is that currently MC does not support synching protocol, in DLNA or any other way. Therefore it can send to this DLNA renderer instead as normal and it's this DLNA renderer (via its dual personality as an Allplay device) that does the synch with other renderers. The JRiver Id as a DLNA renderer won't provide this synching.
If MC incorporated the Allplay protocol, it could act as the Allplay controller instead and talk directly and sync with all the zones.