whites tree frog

I can’t find a good answer on how big they need to be. I don’t actually know how old they are. In their last shed at least two of them have started getting those white spots. They frogs are about the length of my index finger now. Is this a good time to start feeding them less often?

Recently (especially when I’m feeding them or watering the plants in their tank) I’ve been hearing kind of chirping noises? It’s definitely not crickets. Unfortunately I haven’t been able to catch it on video as it’s short and rather random. They’re definitely too young to be making breeding...

As far as I’m aware vertical pupils are generally for ambush predators and horizontal pupils are generally paired with eyes on the side of the head and are prey animals. Does anyone know why they have horizontal pupils?