As far as the greens/veggies go, most dragons don't eat many, if any, before they are up close to a year and a half/2 years old, when they typically switch themselves over from tons of bugs to tons of salad. But you're right, offering a variety of not only greens/veggies and bugs is key, as a lot of Dragons do get bored eating the same thing every day (can't blame them)...
Healthy, fresh greens for Dragons include Collard Greens, Mustard Greens, Turnip Greens, Dandelion Greens, Bok Choy and Pak Choy, Escarole, Endive, Arugula/Rocket, and Chard...For fresh veggies, try any types of Squash, like Butternut, Spaghetti, Acorn, Yellow, and Green/Zucchini, all colors of Bell Peppers (red, green, orange, yellow), green beans, pea pods, and then a little broccoli and carrot in moderation.
As far as his bowel movements, it's fine if he doesn't go every day, or even every couple of days. Usually babies and juveniles that are under a year old go more often than sub-adults and adults over a year old, but there is no set rule or pattern as to how often they need to go. A good rule of thumb is don't get excited or worried until 10 days has gone by without a bowel movement, at that point you can assume that he might be a bit constipated/impacted, and at that point you'll want to mix a jar of Prune Baby Food mixed with 2-3 tablespoons of plain, raw, canned pumpkin (not the canned pie mix, lol, just plain old canned pumpkin, it's all fiber), and a little water or unflavored Pedialyte, mix it really well, and drip it on his snout for him to lick off, then let him bask for an hour or two, then give him a nice, warmer than average
bath for 15-20 minutes. Usually they'll go after one or two cycles of this laxative slurry protocol...But you don't need to do anything until the 10 day mark goes by. If he goes 2, 3, 5, 7, 9 days without a bowel movement it's okay.