I have some cookie like treats that i guess were home baked, from Tisol (pet store here) my guys LOVE those their apple thingers lol, Also they LOVE yogurt covered hay balls and Yogurt covered papaya and yogurt covered sunflower seeds.
Theres nothing wrong with giving a young rabbit fruits/veggies under 6 months if theyve been brought up on them slowly, heck my guys got massive ammounts instantly when they were about 10 weeks never had a veggie/fruit before and i just handed them a large bowl full (they were super thin and didnt seem like they were gaining weight, werent eating their hay so i just loaded them up on whatever they would eat, veggies and they were fine from there)
But treat wise thats healthy, my guys LOVE herbs, basil, sage, oregano, Lily loves dill, im sure there are tons of home baked treats you can make that are healthy too, do a quick search on here i believe theres a few threads.