The fun thing about speculative biology is that there isn’t really an upper limit. It can always get even more horrifying.
Here, I’ll give you an example: you know how in Pokémon lore, Cubone allegedly wears its mother’s skull as a hat?
Some believe that this means Cubones have a fixed and dwindling population, because there’s necessarily at most one offspring per mother.
In fact, no such population limit exists, because Marowak – the adult form of Cubone – possesses a sacrificial “head”. A Marowak’s brain is located in a reinforced compartment within the thoracic cavity; what appears to be the head is actually a limb containing only a simple sensory ganglion, as well as the usual sense organs. The female Marowak sheds this limb shortly after its offspring hatches in order to provide a food source and protective shell for its young. The limb then regrows in a matter of weeks; during this time, the “headless” Marowak is blind and deaf, and must be cared for by its mate.
So the Eeveelutions in Extreme Evoboost are actual Eeveelutions, and not just spirits or whatever
As in, whenever someone uses Extreme Evoboost, eight Eeveelutions have to drop whatever they’re doing and run to where Eevee is to give it a stat boost