FFVII Remake:
GC 2015: Final Fantasy VII Remake wont run on Luminous Engine
FFXV:
Not official source unfortunately, but I had a conversation with another developer. (sry for the wrong english)
Me: As i know, FFXV use Luminous Engine.
Dev: No. The FFXV use hybrid engine (LE-UE4). The Square is licensed the UE4, because the Luminous is not working. They tried, but it is not working. The used parts must be included into the UE4. They have a license, which fully edited, altered. Of course, therefore, pay a lot more than others, but this is also an option at the Epic.