So do we look at it from the point the (Adult to Child) & (Child to Adult) are not migrated to an affiliation? And if that is the case, do we need to fill out the New Affiliation type value for those rows?
In the example you're mentioning (Adults and Children) that would be an association. There's no affiliation created between the two. The Adult would be affiliated to the household as an Adult on both sides of the affiliation. The child would be affiliated to the same household as a child on both sides of the affiliation.
The Adult and Child will be associated to each other, with whatever relationship type of association they currently have. So unless you wanted to change to different association types in v11 than the ones you currently have for the same (parent child, or whatever terms you may use), you wouldn't have to change anything regarding Adult-Child relationship. I think. Hope that helps.