I have used (at Meridian's advice/guidance) AC12s in reverse and they worked fine. However, the Comms were not at all straightforward and basically required a legacy M lead to feed comms FROM the legacy unit into the master comms socket on the AC12 and then the SL units were all right (as were slave legacy from the slave socket on the AC12).

Cinema/Music: Trinnov Altitude32 8-16,218,Cloud 4 channel, Marantz UD5007,DSP5200SE(2+C),DSP3300(4),DSW(2),271,MShort Ceilings,AppleTV 4K
TV: Marantz SR7013 Wharfedale Diamond 9x4+Celestion(C)
Music: Roon,i7NUC8gen,QNAP TS253A, Sony Scala, MS200, Garrard DDQ650,Wharfedale Diamond 12.3
Kitchen: AD88 (bluetooth via i80).