hello! welcome to axolotl parenthood! he is certainly a cute little thing! Couple things I'm noticing right off the bat, he is way too small to be housed on sand. It can cause lethal impaction for axolotls his age when they ingest sand, which he inevitably will when he eats (especially if he is eating bloodworms off the sand like i see in the first photo). I know its a pain, but I would highly recommend removing that sand until he is at least 6 inches. It looks fine grain enough to be ok when he gets larger, but his little system wont be able to pass it now.
Everything else looks good. Be sure to monitor your ammonia, nitrites and nitrates carefully with a liquid test kit (no strips, they are not accurate). Even in a pre-cycled tank, you can have some fluctuations at the beginning as your bacteria colonies accommodate the new waste levels. Weekly water changes are your best friend. Make sure you are removing any uneaten food asap or it will pollute your water. As he gets bigger (and they grow fast!), you will want to transition him onto cut up earthworms. Bloodworms do not offer adequate nutrition for larger axolotls.
Excited for you and your little guy!