I'm sure it will serve 16 people after dinner. We served it and one regular apple pie early in November with 21 guests. We had 1/2 a pie and 3 slices of the tiramisu left over for snacks the next day. Something like that doesn't last long enough to spend time in the freezer so I have no suggestion. I'm sure that info is including in labeling. It seems like it's about $16 or $17
While you're at it tips and tricks for the lady fingers too... I opt for store bought tiramisu simply because I can never get the lady fingers to work right, and I live in a place that apparently doesn't sell them in its bakeries ... Lol. :)
Americas test kitchen has a Tiramisu recipe in their Classic Italian cookbook and it's repeated in their International cookbook.
Sometimes you can find their recipes repeated on various websites - it's too much for me to type and probably against the copyright rules anyhow.
As for the ladyfinger technique, they even have a picture of right and wrong. They say drop the ladyfinger into the liquid (2&1/2 cups cooled coffee, 1&1/2 tbs instant expresso and 9 tbs dark rum) and then roll it over. The whole process should only take 2-3 seconds.
I may make a batch if the supermarket has the ladyfingers and I'll let you know how it comes out.
My wife has had the Costco Tiramisu and shes says it's nothing special although she's not easily impressed. I generally like Costco products(for example they have "real" chickenstock) but the cheesecake they sell is too sweet IMO (can't taste any cream cheese flavor).
From my very limited experience, ATK seems to emphasize flavors in their desserts rather than sugar. I'm also planning to make their hazlenut-chocolate cake and they don't recommend any icing.