I love the name Mowgli!!!
He shouldn’t have a problem with the lip. Give him more time. I don’t give my rabbits treats, because “treats” usually mean fruit. And since my holland lop has a sensitive belly, I won’t tease him by giving the other 3 fruit. So his treat, is just his favorite veggie, which is bell pepper. There are definitely different ideas on safe treats. Favorite veggies are a healthy way to go for treats.
Many folks disagree with giving a 10 week old veggies. I gave my 4 litters grass and veggies when they were old enough to eat from momma’s salad bowl.
Spend most of your interaction time, around food. That should encourage positive images of you in his mind. I’m journaling in the behavior section, about getting one pair of my bunnies to trust me. I plan on starting around food. For their first week in the house with me, I’ll let them watch me go about my bunny husbandry business in the rabbit room.Next week I’ll spend time petting them while I feed them. Give that a try. Maybe focus on bonding with Mowgli first, and once he is comfortable with you, he will feel more confident to step out of the cage. There are many different approaches. I like the food approach. Bunnies are foodies… I’d love to hear how it goes.