Some children you just need to snuggle more. Some need more hand holding, some need more physical affection. Some will be just fine being sleep trained, being taught the routine, and some will have anxiety over being forced into a routine. Of course structure is important, but sometimes creativity is required.
In deciding what approach to take in parenting each individual child, remember that… they are INDIVIDUALS. If you don’t call attention to the differences, but instead try to parent each child to their own needs, they will not notice as much that another child may be parented differently. It will be ever so slight, and the only REAL thing a child notices is when their needs are unmet.