I can’t really provide any reliable information as I don’t know anything about the N7 or CIs in general. The following is speculation as I also haven’t been able to find any real documentation about MFI and there are NDAs and real costs to get involved. But I read somewhere that Cochlear devices are MFI.
My GUESS is that many MFI hearing devices implement both Bluetooth and additional MFI specific protocols and use Bluetooth for pairing (and maybe other features) but use MFI specific protocols for streaming stereo audio to hearing devices. If that is the case, then a typical Bluetooth adapter may pair with the MFI hearing device but not stream correctly. The only way to find out for sure if streaming works is for someone to experiment with transmitters and report their findings to the community.
Good luck experimenting