in fr/lg, the new evos were completely locked until national dex (postgame). in hg/ss, the ones that evolved by unavoidable means were freely available, but anything that needed a stone or a trade item wasn't there until after the e4 (trade items being at the end of kanto).
unfortunately, all of the evos for gen 3 mons are completely avoidable, so if they go hg/ss route they'd be postgame only. but i really do hope they add them, one of my favorite things about playing remakes is to take old pokemon i'd used before and see how they fare with whatever new tools they've gotten in the generations since, and there isn't a better tool than an evo.
