Congrats on your addition.

You are correct that mealworms aren't a good choice for cresteds. Phoenix worms are great if you can get them as they are very nutritious and contain a lot of calcium. CGD should be the staple diet, which you can supplement with insects once per week or just every once in a while if wanted. Your food and water dishes are not too deep--he is large enough that drowning is not a risk unless you have a really deep water dish. Mainly, you want to use a dish that holds just enough food--enough to be consumed within 48 hours time but is not spread so thin that it dries out too quickly. I use 1 oz deli cups for my adults and fill them to varying degrees depending on how many geckos are in the enclosure. A 3/4 oz cup is good size for a single adult or for sub adults.

If you want to give fruit as a treat their favorites are usually strawberry, mango, watermelon, peach and banana although they can eat other fruits as well. Just make sure to stay away from anything acidic like oranges, grapefruit, etc. as they cannot tolerate the higher amounts of citirc acid that those fruits have. You will want to mash up the fruit or make it into a smoothie. You can add CGD to the smoothie too, just add water for consisitency so it isn't too thick. Steer clear of baby food as it is too high in sugar and not healthy.

The throat movement that you see is just normal crested breathing. It is kind of like a frog. And cute.