Oh - and dd1, whilst not hitting, has had a fair few wobbly phases since dd2 arrived. TBH, the best way through I have found with her is simply to mirror how angry she is feeling (y'know, the 'I think you might be feeling really angry or upset right now, and thats ok, but its not ok to do xyz') combined with an Angelina Ballerina book about a baby sister....that one really helped because Angelina has mixed feelings, gets angry and throws her toys around, bursts into tears, etc. I think dd could relate and saw it was ok to hate her little sister sometimes - she started verbalizing it when irritated instead of acting it out.
She has days on end of being lovely, then will have a few days of being stroppy (as in now, the cold not helping) and omg soooo wanting to be in control of me, the world, etc! Firm boundaries and loads of love, is all I know how to do - she's also growing heaps in every sense, gaining skills, independence, so imagine she'd be going through it right now even without dd2's existence
Sorry, those of you for whom older dds are not of interest - bit off topic