I do chocolate mousse with 8 eggs and 200g chocolate and it's fine, but you have to do the egg whites in installments to get them very stiff. If you do it absolutely now and eat lateish you should get away with the timings.
Is the secret ingredient the booze? Can you whip it into some cream and serve on the side for the dairy eaters and give it to the non-dairy person in a shot glass? (or perhaps mixed into some melted chocolate, but that might not work).
Now I'm doubly hacked off at myself because I have thought of a way I could have rescued it, and incorporated the SI (not booze, BTW), but because I have scraped the mousse out of the individual dishes and chucked it into the fridge in one bowl, it is too late.