Don't do pork tenderloin for pulled pork.
The best pulled pork is from a butt or shoulder roast.
How about calling a local good BBQ restaurant and get an idea of the amount you may need for that many guests. Some guests may make a sandwich with 1/3# meat but others may forgo the bun and eat way more. I'd go heavier with pulled pork.
I think a large crockpot of sloppy joes is great but I'd still offer a chicken option. Maybe bbq chicken as well. A crockpot of Joes and maybe 50-100 BBQ wings or so.
If you do all 3 meats, of course you would do less amounts on each, not like huge amounts of each.
A good standby would be plain grilled burgers and dogs.
Have fun!