M.C.
Not much time to type right now but I just wanted to suggest trying more positive reinforcement instead of taking away things and punishing all the time.
Start a sticker chart(or coin/ticket jar) for having good manners, being polite, helping around the house, saying nice things to siblings, etc. Include whatever issues are important right now. Let him help or make the chart himself. Buy some new stickers that he can pick out. Decide how many stickers he can realistically get before getting a bigger weekly reward-something important to HIM. Ice cream, pizza, going to a park or special place, a new toy, etc. Show him that good things come from being nice, having good manners and being respectful. It may sound like bribing and in a way it is but it works because it is positive attention. Right now he knows he gets attention for doing negative things and you want to stop that NOW.
Also, make sure that you and your husband are being great examples of showing respect for each other, having good manners, treating each other and the kids nicely, etc. So many people don't see that they themselves are modeling that exact behavior that they don't like seeing in their kids. Not that you are, just that I see it a lot...especially when I was teaching before I stayed home with my kids.
Good luck, it's a tough age but it's so important to stop the negative attention before it gets worse.