Hi author of the project here! Someone pointed me to this thread so thought I'd chime in.
I hadn't seen the wolfmidi project before, it certainly looks like an interesting mod. A couple of people have asked if Tandy 3 voice sound could be supported, since I supported the 160x200 16 colour Tandy mode. As far as I understand, the music format used is basically just a stream of OPL commands which makes it tricky to target other sound devices so having something that converts it to general MIDI could be really helpful.
I'm sort of surprised nobody has made an EGA version yet since from a cursory glance there are a lot of similarities to the Catacomb 3D engine, at least with the way compiled scalers work. Certainly a possibility! There are a couple of EGA style sprites that Romero posted a few years ago but I've never heard of an EGA beta.
I'm also considering a Hercules mode which could potentially be faster than CGA if I can use page flipping. Plantronics ColorPlus mode is also a possibility, although would likely be slow due to the way the memory is arranged. I've also had a request on Github to support 640x400 monochrome mode too, which has a similar memory layout to Hercules with 4 line interlace.