Wheatley is an adorable name, and that’s such a cool story! I got my first leopard gecko when I was about the same age as you are now. Look out, they are addictive! My oldest turns 18 this year.
I know exactly what you mean about wanting to get everything right. For years I fed my leos a diet that was too high in fat, though I didn’t know it. I wasn’t a vet yet and wasn’t corrected by my guys’ exotics vet at the time. Fast-forward 10 years, and some of my older guys started developing sometimes fatal diet-related cholesterol tumors that affect their nervous and reproductive systems. I only figured it out on my own, as a then just-graduated vet, because I always have my guys necropsied if they pass away inexplicably.
I beat myself up about it when I finally put all the pieces together, and I still do to a certain extent. But ultimately I came to the realization that mistakes happen, just as you mentioned, and that there’s no way I could have reasonably been expected to know any better at the time. My intentions were the best, and I did the best I could to educate myself, and that’s the best anyone could ask for, right? Though I do think I didn’t take it seriously enough that imbalances in husbandry are almost always behind most pet reptile illness.
Since you just have Wheatley, I agree with your assessment- it might not be a bad idea to replace his wooden hut with a plastic one, at least for the time being (some wooden huts are small enough to carefully boil in a pot on the stove- just don’t use ‘for people’-dishes/pots/pans). I still have a ton of wooden huts and cage furniture, and they are almost impossible to thoroughly disinfect, so I recommend a switch early-on, before you’re up to two dozen geckos. heh.
I’d say that giving mealworms potato, apple, and carrot is more like giving the mealworms the food they need to live. Gut-loading them means feeding them something that will correct their inherently not-so-nutritious nature, especially with regards to their calcium-phosphorus balance. Leos need a diet with a 2:1 ratio of Ca:P, and the common feeder insects have way too much phosphorus. To properly balance an insect will vary depending on species (e.g. roaches need be fed low protein diets ONLY, mealworms are super high in fat and shouldn’t be the solo food item longterm, etc.). I would not personally recommend dusting insects with calcium powder at every feeding, especially not calcium powder with D3, but many people would disagree with me. I totally feel you about watching life cycles- I’ve grown rather fond of silkworms and silkworm moths in particular.
Honestly, you sound incredibly caring, knowledgeable, and devoted to the health of your little man- he is lucky he found a home with you!