>>38284147Interestingly Blastoise was switched with the original final Wartortle evolution, and also likely had a pre-evolution of its own (in these sprites you can see a bigger Wartortle as well as a little thing that's probably a baby blastoise with a bubble coming out of its nose and back.)
There's a small chance these backsprites are bullshit, but even if not, internal data (such as the cries) points to a switcheroo.
After gen 2 they knew what they were doing, so Greninja and Decidueye's evolutionary paths were very deliberate