Right, i dont't know about ZCash, but the one about Dash has been thoroughly debunked and has not been shown to work on the real network and most likely doesn't.
"thoroughly debunked"
Please show a similarly serious and rigorous scientific paper which does so. If not then it is just a bunch of nonsense shilling from bag holders. Indeed I remember seeing a comment from an actual Dash developer (not idiot community shills) stating that it was in fact a valid attack.
All of the above basically devolve to the same overall flaw and methods which is optional privacy not working because of too little usage in practice and information leakage from the transparent transactions leaking into the private ones. They apply to any coin with a similar approach, including small ones that nobody bothers writing papers about.