If you are having a private event (not open to the public), and are serving food only to your guests, your caterer does NOT need a Temporary Food Permit. The caterer does need a Catering Permit from the KCMO Health Department.
If you are serving alcohol and not selling alcohol – including not having a tip jar, to your guests, you will not need separate alcohol permits fro Regulated Industries. If any money is changing hands between the server and the guest, then permits are required.