1. So, what is this type all about?
The idea behind a Beast-type is to put all regular animal based Normal-types away from the Normal-type. This way, Normal can just become a default type for odd non-elemental species, while regular animals wouldn't have to both with it.
2.Where does this name come from?
The name comes from the Beast-type monsters from Yu-Gi-Oh!, SMT and Digimon.
3. Does this type have an in-game source?
Generally speaking, no. Only the fact that most mammalian based species tend to get put in Normal-type. Field Egg Group is more of a "terrestrial animals" thing.
4. What would be the ideas behind such a type?
It would largely be a fodder type for mammalian and carnivorous species. Presumably reptilian species, birds and fish wouldn't be in it, as in most other monster franchises, Beasts generally refer to mammalians.
5. What would be the type interactions of such a type?
6. What would be the distribution of such a type?
Very large. The main reason this type is desired is because it would be given to MANY Pokémon, effectively buffing a large portion of the metagame in one swoop.
In addition to regular species, mythical beasts such as Kirin and Kitsune can be added to this type as non-elemental variations of their respective species, as opposed