@jwashington
Well, very hard to catch your points (Sorry, for my poor English),

MMM-AssistantMk2 and MMM-Hotword couldn’t be the solution of your issue?
MMM-AssistantMk2 is using service version to output visual response
And MMM-Hotword is the awakener with Snowboy.
Two modules are well combined and implemented into MM system directly. So you can control MM or its modules with these modules. (Of course some HARD configuration will be needed. and installation is not so easy.)
But the goal of the module is not becoming alternative Google Home device. it can gives a voice command feature for controlling MM.