Hmm. I'm not a chemist, if it goes milky in the base step to me that indicates there is alkaloids there. (I absolutely love pouring my lye water into an acid filled with alkaloids and watching all the clouds form!) Your description reminds me of when I put just a tiny bit of lye water in and it precips alkaloids but the acidity dominates and the alkaloids redissolve. 50g in 200ml should be plenty strong imo. How much vinegar and what % strength did you add? Usually I find it will go strongly milky and then it settles at the bottom which is what you seem to have, but you're saying it all redissolved so where did your precipitate come from?
That white precipitate isn't going back into the shellite? It looks dmt like to me, especially knowing you extracted from acuminata which seldom would contain nothing.