I was curious as to what the park considers a handheld baby. Several of the rides our daughter seems really interested in riding but the signs so no hand held babies. What is the rule on this?  Do they have to just be ablE to sit up on there own?

I always took it as being able to sit next to you safely, and not being held on your lap.

Our little girl was about to ride the Tiques today and a few other rides. 

What a cute family! Looks like they were having a great time. Thanks for sharing!

From the park Guest Assistance Guide:

Quote

Hand-held Infant: Hand-held infants are children who are unable to independently walk or maintain seated postural control and will only be able to ride
the following rides with a supervising companion: Boo Blasters on Boo Hill, Eiffel Tower, Grand Carousel (seated on a bench), KI & Miami Valley Railroad, Character Carousel (seated on a bench), Splash River, Coconut Cove, Lookout Lagoon, Castaway Cove. Participation
or water depth may be restricted at Breakers Bay and Tidal Wave Bay. Hand-held infants and their supervising companion may also enjoy Splash Landing, but may not participate on the elevated sections of the attraction.

https://www.visitkingsisland.com/help/rider-height-safety