I was thinking about it, and I think the patcher that exists will work. Considering the sound blaster emulator needs the TSR, you can't use the Sound blaster function with just a simple patch, but Adlib can be made to work since no emulation software is needed for that. Since the parallel port for the Digispeech Plus is the same address as the OPL2LPT, I don't see why the patch wouldn't work.
The only way to get Soundblaster functionality is to try and get the cloaking system working. As long as a game's DOS extenders comply with DPMI, VCPI, or DPMS standards, it seems like it should work, since those memory interfaces are meant to allow switching into and out of protected mode as needed, at least as far as I know. I will be the first to admit, I am no master of DOS drivers; if there is a master of DOS drivers around here, I'd be happy to collaborate with them, since if we can get this working for the Digispeech Plus SoundBlaster Emulator, we should be able to get it working for the OPL2LPT TSR as well, and in that case, everyone wins. Especially since the Digispeech Plus is no threat to the OPL2LPT project since it is so rare. In fact, I would not be surprised if the ones that were acquired recently were the only NOS Digispeech Plus's left in the world. The only ones I have ever seen mentioned, and that is maybe one of two mentions throughout the entire internet, both temporally and spatially, were used.