Useful that the page says frame sizes differ between characters, because that is the part that bites at import time rather than at purchase time. The question a buyer runs into straight after is where the feet sit. If the contact point lands at the same fraction of the frame height on every character, the differing sizes cost nothing and you just scale. If it moves between characters, each one needs its own pivot offset in the engine, and that is where an afternoon goes.
If the anchor is already consistent across the six, saying so on this page is worth more than another animation would be. That is the difference between a pack that drops in and a pack that has to be set up.