i know and it's driving me batty because it shouldn't be this hard for anyone. at least we are slowly making some progress in narrowing down the possibilities. i'm trying to figure out instructions for what to try next . i'm invested in it now, and if nothing else, *I* want to know what caused things to go sideways.
but for your part, if i knew how to get a private modpack posted up through the launcher i'd have done it for you, simply because you deserve better than the headache you are getting from all this.