Can you breastfeed her through tantrums and feed to sleep if she is resisting? (I saw you mention bf so I am assuming you are still feeding).

Breastfeeding seems to be paramount to my kids at two and is the best parenting tool I have when they get over tired and over stimated.

Otherwise keep food and drink on hand always, do lots of skin on skin and cuddles, lots of tickle games to get the sillies out and be very firm about violence. Ds has to sit or lie on the floor when he hits.

It's an aggressive age I think and they do lash out at older siblings. Dd sounds like your eldest And will NOT move away from ds but just provokes him. It's tiring!!