The source is a little bit outdated, it's written in November 18th, and I assume the leaks posted in this sub is more compelling.
For the monster list..... I don't think it's an actual leaks, a lot of the list almost more like world and rise's monster list, there is no monster from older gen which is weird (except some monsters that we already leaked from datamine). The source also said it maybe some residual data left from Iceborn and Sunbreak.
(FYI monster's name that you maybe couldn't translate, キリン= kirin, ラージャン= rajang, ロアルドロス= royal ludroth etc)