IMHO lifejackets are not a good choice for toddlers. Since you can't explain them beforehand what might happen and how to react when in the
water they will likely panic wildly. And the parents also. You just don't want them to reach te
water at all. We chose to use a harnass with a tether attached to the back and to a central point on the
cockpit floor, the length so adjusted that they could reach the coaming, but not over it.
At the age of three or so, when more freedom is required and explanation is possible we switched to foam filled jackets. Also great bump-stops. At the age of 8 or so self inflating jackets. Below
deck wearing a
PFD is not necessary and even potentially dangerous.
A berth with a leecloth is also excellent for
children. BTW, both our children are still alive, QED