Hi P.
This is just my opinion. I think with the age range of your children, I wouldnt do it for right now. It will be hard to design a party for 4yr old boys while keeping in mind little 1 yr old girls. Do you mean just for a family party or will he have friends that come too? Her 1st party has to be her own. Pump it Up or Chuckys would of been great, but for a 1yr old I would say not. I have always done big family parties for my kids til they are 5. When they are in school and have more friends, then I do a big friend party and a small family party. I would do them separate, her's isnt til after the holidays anyway. If the cost is the issue just try and scale it back. Your daughters party could just be pizza and cake at the house, she really wont care!! Let us know what you decide, the idea could help all of us!!