About the very hard mode, I thought it was mentioned in the 2nd fan briefing (where the desert and snow areas were first announced), but looks like this mode wasn't mentioned there, there hasn't been any announcement related to a very hard mode after all.

Dataminers found stuff related to a very hard mode in the closed beta files though, so even though it wasn't announced that it will be available in the release version, even if it ends up not being available there, it'll be available eventually.