Being a remaster, you can expect better graphics to fit the machines of today. There’s even an additional photo mode, which sounds a little redundant. But it could be useful if you like seeing the distance between a hostile spirit and you when the Camera Obscura is able to banish them.
As mentioned, Fatal Frame: Maiden of Black Water will be available on basically all platforms when it comes out. Specifically, it will be on PC via Steam, both generations of both brands of consoles, and the Nintendo Switch. But there’s no specific date as to when it will be out beyond the very vague 2021.