How much meat

Figure 4 oz total meat (finished weight, not raw) per person, so in your case 2 oz pork and 2 oz chicken. Also figure 50% yield due to water/fat rendering, bones, etc. So you need 4 oz raw of each per person, so 800 oz or 50 lbs of each. Pork butts average 8 lbs so you are looking at 6 - 7 butts, probably do 8 to give yourself some cushion. Similar for the chicken.

Now this doesn’t apply if you are feeding a bunch of linebackers, wrestlers, etc.

In my region (Smack That Butt BBQ, you are in my region) you'd better have at least 4oz of pulled pork minimum per person as it is king in this region of the world and you will runs out and upset guests otherwise. The pulled chicken you can probably get by with 2-3oz per person. I'll say that is a ton of chicken to have to cook to get the weight needed for pulled chicken (which is why I don't offer pulled chicken). Post your results once you have completed the event so we can see how it goes. Good Luck!

4 oz of bbq per person will get you fired.
Figure 50% loss on pork
Cook boneless skinless thighs for the chicken. figure only 35% loss on that.
100# of pork and 2 cases of thighs will get you thru.

Leftovers go to the client as they paid for it.