Do Comp & Coll both need to be added/declined?

This depends on the State.

If you are in a State where both are required, the api will respond with a message similar to this: "Vehicle must have either both Comprehensive and Collision coverage, or neither", located within the specific coverage selection. Furthermore, the quote will have a status ofcollecting_data.

Do the deductible amounts have to match?

Again, this will depend on the State being quoted. Look out for those error messages in the response body!