I'd imagine any smart working team would negotiate this heavily. This setup appeals heavily to someone like me (with 2 other people specifically), but I would also be personally be asking for $300k+ salaries for each person + signing bonus + RSUs. It would be a happy medium between a lengthy and pricey acquihire and getting 3 developers/PM people who you know already will work well together.
I'd recommend that anyone doing this that they negotiate their salaries very heavily.
What experience are you drawing on for that recommendation? Big companies don't typically negotiate wildly on salary, as it's tied to a leveling system that breaks too many things if your numbers don't fit. They would have to negotiate on levels and make everyone VPs to meet your salary demands, which would cause other problems. So, this might not be the best advice. Acquihirees get a few knobs to turn, but salary is the least turnable.
I'd recommend that anyone doing this that they negotiate their salaries very heavily.