I don't really understand the question. You talk about wanting to spend $50/plate which implies you want fine dining, but then you are asking about stuff around College/Spadina. Lots of great Chinese food on Spadina but fine dining it is not.

Use Just Eat for deliveries (https://www.just-eat.ca/), it is just an order taking service that is used by many of the Chinese restaurants on Spadina. The food is delivered by the actual restaurant. It's like Seamless or whatever nonsense they are using in SF except it uses fax machines and doesn't operate under the pretense of being an innovative tech startup. New Ho King and the like will deliver directly to campus buildings, they know all the names, especially the engineering buildings. Deliveries until 4am or so.

Pizza - do you want good pizza or cheap pizza? These are completely different. Libretto has a downtown location now for good pizza. It's more than $3/slice or whatever the places on Harbord/Spadina charge these days. You don't need to "quest" for pizza at 10pm in Toronto. It's not Yellowknife, all the big chains will deliver until 1am.

24 hour breakfast near U of T - Fran's is pretty much your only option from midnight to 6am.

Italian - not sure what you mean by good, the best Italian places in Toronto aren't downtown but if you just want non-fast food Italian there's a Mercatto on College.