I found a new vastaya

Definitely a possibility. As it stands though we don't know if the Minotaur people are a type of Vastayan or their own separate race. For example Yordles exhibit many of the properties of the Vastayans including animalistic features and magic that alters their appearance (Though possibly through Glamour rather than Grammar (Aka magic that changes how one sees something rather than changing the thing like shapechangers)) but based on some rioter comments Yordles do not seem to be the same as Vastayans.

Where the minotaur fall on that is an unknown, but due to it being a specific named group I would hedge my bet on currently them being unrelated though that could change as I mentioned.