B.M.
Hi, Relax. This is just a little jealousy or attitude. When someone says don't do that, she just has to do it! At this stage she is probably feeling a bit left out. The baby takes up more of your time. People come over to see the baby. It used to be all about her. Now she's sharing the spotlight. Punishing her just makes her resent the baby even more. Now he makes her get punished. It's all his fault. She really doesn't get that she's being aggessive. I know that you have no choice to but to do a time out after these incidents but make sure she knows the reason for it. Explain it over and over. Include her when you change the baby. Let her rub lotion on his hand and then praise her to the heavens for it. Let her help hold the bottle and do the same thing. When she understands that she gets a great reaction for good stuff she'll ease off on the other stuff.
Make sure to set time aside for just you and her. She had it before and she probably wants it again.
I sympathize with you. I also live on Staten Island. I have four children 23 son, 20 son, 16 son (autistic) and a 12 year old girl. My husband works constantly. When they were young there were some days I felt abandoned, lonly and overworked. Most of the time I realized that I liked being the only authority in the house. Get out as often as you can. Even if you just walk around the block. Go get some ice cream.
You're doing a great job. Take care of you just as much as you take care of them. It's all a circle. If you feel good then they react better. If they react better then you feel good.
Good luck.