https://www.dinopark.es/es/algar
This is open all year as are the waterfalls.
Water parks will be closed.
https://www.souldpark.com/ocio/parques/alicante/
Car hire is very expensive at the moment so you may want to consider hiring just for a day or two. There is a tram running up and down the coast to get you to most places.
https://www.rome2rio.com/map/Calp/Benidorm
All restaurants are child friendly.