Sorry, but the bottom line when it comes to wakes was stated above:

"A vessel operator is always responsible for any damage
caused by the vessel's wake."

It does not matter how far his wake went. If his wake is that large,
then he needs to go slower to control his wake.

Even if the 40' boat had the required personnel, it still would have
capsized. An extra man on that boat would not have saved 20 people. If
they fulfilled the other requirements i.e. number of passengers,
equipment, etc, their liability is greatly reduced.

The seats weren't fixed? I'm pretty sure that's not a requirement.

John