rayarachelian defeated the brand software for Multiplan a few years ago
Yup:
https://lisalist2.com/lisalist1/2496.html (warning, it's full of Rick and Morty memes)
I'm not sure if this will work the same or not, but I plan to use the same approach. But basically there, I went around brand and modified the multiplan executable itself after seeing how brand works. though yes, I started with brand.
However, this is also an excuse for me to try to get Xenix going on LisaEm as well - the issue seems to be that it doesn't like my profile emulation, so I'm going to try to either placate Xenix or if I can disassemble enough of the driver, to use High Level Emulation to get around it.