The Phantom is more so confused as to why Velgrynd is acting as her ememy even though the timeline the phantom originally came from had her as Feldway's/Michael's ally. This is mainly used to indicate the existence of different timelines, one where Velgrynd is Feldway's ally, the other where she isn't.
Pretty much, which we use to prove that Chloe only travels to separate timelines. Besides, Diablo said reversing time is impossible, so Hinata's theory which is apparently confirmed by Luminous doesn't make sense.
And we literally have Clayman's side story showing an alternate timeline's events...
None. It's just a Void of Non- (negation) that contains all dimensions. A Void that Space, Time, Dimensions (up, down, left, right, etc.) yet is Infinite and incomprehensible, where Ramiris can insert any number of Dimensions (via Small World) given sufficient Magicules.
BDE3? Probably, but it's better to argue that for the World Gap given it has more context for such.
Laws encompass Subspace too given skills of a certain level work in subspace as well, so it's same to assume it's created by Veldanava as well. Skills that work on it are said to transcend all space, time and dimensions.
If it's just tier 1 in general, better to argue it with actually dimensional stuff; Imaginary Number Space, 4th Spatial Dimension, Hyper Space-Time attacks, Time travel to before retroactive destruction of space-time, etc.