Unlimited pellets are not best at any age. In adults, it can cause obesity, but in young rabbits it can cause enteritis or other digestive imbalance. When I am weaning young kits, I offer 2x their adult ration daily. Once they are weaned (10-12 weeks of age), they're offered 1.5x their adult ration. This is plenty of pellets to help them grow, but also encourages them to eat hay throughout the day.
Along with that, I feed strictly timothy hay (to any age). Rabbit pellets are formulated to be a nutritionally complete food. As long as you're feeding an age-appropriate pellet, supplements are not necessary. For a younger rabbit, the feed should be higher in protein and fat than what you would feed an adult rabbit (as far as pets go, anyway). Adding alfalfa on top of an already balanced alfalfa pellet can make the diet too rich in calcium and other nutrients, even for babies.
Also, as far as veggies go. If he was not raised on veggies, I would hold off on introducing them until closer to 4-6 months of age. When rabbits are raised on them, it's fine to introduce them a bit earlier. But otherwise, it's better to hold off until they're adults and their digestive systems are less sensitive. After all, there is no reason to rush it.
Hope that helps!