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I doubt we're going to get split evos, or even alternate forms. The Chinese leaks, which have proven to be consistent and correct, didn't mention them. The concept art leaks didn't show any hints of this either.
And if we do, they're likely going to be very similar to the original designs. Probably just a palette swap with a couple of changes, like Meowstic. Pokemon that have substantial differences in appearance have their own separate spots in the pokedex, like Burmy and Mothim.
Don't get your hopes for a water/fighting Ballio type. At best, you'll get a palette swapped Entermaid with a different stat spread and typing.