I don't think everyone will take 4 oz of each side. Go to SoEzzy's calculator on this tread or try one of the other ones. They are pretty accurate.
I would price the chicken at least the same if not a dollar more. You will need about 60 oz of chicken, which is about 4 lbs. You will need 15 lbs of cooked pork or 25 lbs of raw pork at a 60% yield. Another thing to consider, how many adults and children will be there? I would cook enough chicken so you have extra to use at your place. Chicken is labor intensive to pull, so make sure you buy big enough chickens. I can only get 3# average chickens from Sysco. They are fresh. If you have time buy the frozen and get the larger chickens. Call if you need any other help.
Team: Pyle's BBQ; Yoder YS640; Good-One "Trail Boss" 60T; Homemade rig; 22" Weber Kettle w/rotisserie ring; Big A$$ Rotisserie; BGE-Small; Weber Kettle Gold, Weber OTS, New Braunfels offset smoker.
Saddles BBQ Bistro