Didn't think I'd see another one of these.
Given they went on with the 5th gen, there won't be a third game with HGSS. That and on top of 'they didn't remake yellow', HGSS already has most of the crystal-only elements in it that GS didn't have, so you can consider HGSS as a crystal remake already. (Eusine/Suicune plot, Battle Frontier, extended 8th badge part akin to Crystal's rather than GS', etc).
As this has been had many times before and there's little else to discuss beyond 'no, there won't be a crystal remake', closed.