Hello and welcome to the forum! Any rabbit will take time to get adjusted to a new home. In fact, because it is so stressful for them, it is advised to completely ignore them for the first 48 hours. That means don't even try to pet Peppermint yet.
The best way to get them used to you is to spend time -- lots of time -- sitting in their area. Don't try to approach or pet them or they will just learn to fear you. Just sit and let them approach you. When they do approach you, ignore them. Yes, ignore them! This is how they learn that you are "safe." After a number of days of doing this, you will get a feel for when one or the other may be ok to be petted. (A bowed head is an invitation for you to pet them.)
Treats should not be offered to Peppermint at all for a few weeks. It isn't good to offer treats (or anything new to a diet) during the first few weeks a rabbit is in a new home. Hay is the exception. Hay should always be available.
I noticed a treat bar of seeds, corn, etc. hanging in Peppermint's cage. I suggest removing it. Rabbits aren't supposed to eat seeds and the hulls of corn kernels can cause gut impaction. I'm afraid petstores sell too many "treats" that are either not healthy or even harmful to rabbits.
The better treats are fresh fruit, but they must be severely limited. They shouldn't be fed at all until your rabbits have been transitioned slowly to a healthy diet that includes unlimited hay, plain pellets, and daily greens. The greens have to be introduced very slowly, one type at a time. You can see more about greens and treats, etc.
here.
When you are getting a bunny used to you, hand-feeding is a good way to get them to warm up. But since actual treats (like fruit) need to be so limited, it is often better to use something like strands of hay, individual pellet feed, or (if they are accustomed to greens) a sprig of a green. The fact that the food is coming from your hand "transforms" it into a "treat."
As for toddlers and bunnies, I would not suggest you allow your little ones to feed the rabbits at all. It isn't a good habit for them to get into because who knows what or how much they offer when your eyes aren't on them. And, yes, a persistent little finger that smells like whatever treat was last held, could get nipped by accident.
It's also advised to train your little ones to never, ever pick up a bunny. They need to understand that they should only pet bunny while bunny is on the ground/floor, and only when you are there with them. (I have no idea if you are already aware of this, so figure it is better to be safe and mention it.) It can be a challenge to teach them to respect a bunny's body language. There are times of each day that a rabbit will not want to be bothered or pet. If a child doesn't understand this and insists on petting anyway, it is possible - after several bunny warnings (or none) -- that bunny will lash out or run off. This behavior, repeated too often, can cause a rabbit to become withdrawn or aggressive.
There is more about bonding with a bunny at
this page.
cookie and peppermint (white) 
