Does anybody have suggestions on a birthday party idea for a baby turning one and a little girl…

Does anybody have suggestions on a birthday party idea for a baby turning one and a little girl turning 3??? Not sure what will be open august - October

Also another question I'd like advice on. I was thinking of doing a party for Savannah and Makayla the same day with family and friends because they are yet still little so I don't think they'll mind. And then do dinner and something just for them on each of their days. Is that a good idea or not? Opinions please