Hi J.,
I'm a therapist and a sole parent of two boys 3 and 5 (my husband died just before our 3yr old was born). Managing them on my own is definitely a challenge sometimes. My 5 yr old has never given me any trouble, my 3 yr old is a little bit mischievous and definitely more of strong personality. My suggestion to you is to be VERY consistent with whatever punishment you give him. You can't ignore it, that works good at a younger age, but now you must correct him so he knows it's not a positive behavior and each and every time he does it, he will have earned his consequence...whatever you choose it to be. And the consequences have to change as they change, when he sees that you're taking away something he likes or whatever you choose, he'll get the idea that it's never a good thing to do. It takes patience, but you'll get it and then so will he. He's probably a little jealous of your daughter getting older too..so be sensitive to that too, he's at a tough age. Good luck!!
D.