I know this isn't actually advice or anything, but maybe she's jealous? A is a big boy, old enought o be of help to you whne you need it, and E is a baby, need ing help and your attention, but she's in the middle, not quite big enough to do it herself or really be helpful (just a pita, I know I have one of those too!) but also not so small she really needs your help all the time like E does. So to get more attention she's doing naughty things cause she doesn't know how else to do it, kwim?
If it helps any, my kids are getting really rough and physical with each other too. Generally I send them to their room, or tell them to sort it out! I'm over running to them to help when they're just egging eachother on to do dumb things that gets the other one hurt. Though for you with E, she's too little to do that with. Sorry babe, no ideas. But will a do?