Blended Family Adjustments

Question:

Hello. My husband and I have been married 1 year. We both have a son from previous relationships. They are only 3 months apart and are now seven years old. They were friends before we were even dating. There personalities are very different. My son’s great qualities are that he is athletic, sensitive, outgoing etc. My step son’s great qualities are that he is very intellectual, responsible, laid back etc. My son’s weaknesses are that he is whiny, independent yet he can be a follower and hard headed. My step son’s weaknesses are that he is very immature, manipulative and a know it all (If he doesn’t know he will act like he does). I am telling 
you this not to compare the children but to help you better know my concerns. 
One of the problems is that my step son is seven years old in the second grade and he is still attached to a stuffed animal named Buck. He carries him every where. We do not allow this but his mother does. If we see him with her in the store or where ever, he has it with him. He even