Each child is an individual. Don't assign roles. No one needs to corner the market in any endeavor, so encourage children in all pursuits. Treat children uniquely, not equally. Don't get bogged down in who got how many pancakes and how big they were.
Kids sometimes act out in hopes of getting attention.
As little as a half hour a week can help. Don't discuss siblings. For adult siblings It's never too late to mend a broken relationship. A sibling's put-downs can have a terribly negative impact. Support each other in good times and bad.