M.L.
When our children were little, we decided that if we were to die they should be raised by a couple with whom we had (and have) been friends since college days. We chose them because there is dysfunction among our relatives. They were agreeable to being specified in our wills. They wouldn't have raised our children exactly the way I'd have preferred, but it was the best choice out of the options we had. Actually, it would have been similar. Our children would have grown up at least with good educations and good values, and I was trusting to God for the rest.
But you and your husband are thinking about a good subject. Check your state laws; it could be that if you don't specify who will take care of your children in such a sad event, then the courts will decide, and your preferences won't have much to do with it.