We buy most of our food and make it ourselves when visiting Maui, because we find most restaurants are expensive and not that great (other than fine dining). However we always eat at Jawz.
We first discovered Jawz while driving out to the beach and stopped at the truck for amazing fish tacos. The next year we discovered the restaurant in Kihei.
It's very kid friendly - you can dine in or take out. It's not fancy but it is delicious and there is something for everyone in your family.
You will be happy you stopped.

We absolutely loved Cannon Beach and it's sleepy little town.
The beach is so big that there is so much space, even in the middle of summer. Our children had a blast flying kites, digging and swimming and watching horses.
The town itself doesn't have a real grocery store, just an expensive corner store, so definitely buy groceries on your way there. We made most of our meals in our cabin, but had clam chowder at a local restaurant.
We found it warm enough to swim in August, but it can be quite windy too.
The trek to haystack rock is fun and we found the beach was easy for our stroller.

I have been to Pike Place Market many times and I enjoy it most when I am without my children. It is very busy and hard to find parking if you were driving. So usually we are on foot coming from somewhere else and you need to walk through some seedy areas of Seattle to get from the downtown to the market.
That being said, if you are a relaxed kind of parent and have a good handle on your kids it is fun to visit, and there are lots of great shops along the way.

Even if your kids aren't interested in snorkelling they will enjoy this beach. if you don't have a car your hotel can probably help get you a limo ride, taxi or tour. it is worth doing while in Honolulu because it is such a calm shallow place to snorkel.
The only downside is that it is very very busy and touristy, but if you are a tourist, who cares?!

The road to Hana is really neat and a must do on the list of Maui. But I wouldn't recommend taking kids who get motion sickness, or don't like long car rides. Wait until your next trip when they are older.
If you do go, it is worth picking up a little tourist guide so that you know where to stop along the way.