Yes I know what you're referring to, but you said the PokeFamiDX adapter doesn't support the VRC6/VRC7. If that were the case then the games wouldn't boot at all. The problem is the NOAC sends the expansion audio signals to ground or are incorrectly wired. That's a different problem than say, NOACs refusing to boot MMC5 games like Castlevania 3 or Uncharted Waters at all.

As for why the adapter that's going to come with the RDP won't work on other Super Famiclones or the real hardware, the answer should be pretty obvious - It must just be an NES 72 to SNES 64 pin adapter that doesn't do anything but allow NES games to fit into the cartridge port. The NOAC is inside the RDP itself, and that's what runs the NES games. Since what comes with the RDP is only a pin adapter without any insturction set and NOAC, it will do absolutely nothing when fitted into other consoles, even the RetroDuo as that system has a unique board for NES games.