I would say 1/2 LB to 3/4 per person.

Especially since you consider cavadil plural, I'm pretty sure you have an Italian/American pronounciation of cavatelli that's fairly common in the East, at least. Cavatelli are small pasta shells that look a little like hotdog buns.

Cavatellinis a pasta made from flour, eggs, and ricotta and gnocchi is made from potatoes

Orzo is a type of pasta that resembles rice.

There are a huge number (over 400) of pasta types including whole wheat, flour, sheets, strips, Fresca, and spinach. Other pasta types are cavatelli, capunti, and corzetti with a complete list found online at pasta sites like Garrubbo.