Question

Actually, it is 24 hour visa free transit and there is no visa of any kind.

Your itinerary is definitely eligible for 24 hour visa free transit and you do not any kind of visa. It is allowed to have multiple stops within mainland China when traveling on 24 hour visa free transit and the entire transit time should not exceed 24 hours. You are definitely within the frames of all current rules.

Upon your landing in Guangzhou the first thing that you will do is to approach 24/144 transit counter where you will apply for a temporary entry permit. Here you will present your flight tickets and after a short check, you will be granted a permit to cross the immigration because your next flight will be a domestic one. This application is free from any charge. Upon arrival in Xiamen, you will cross the immigration again, but now to exit China and to catch your flight to Vancouver. Basically, this is it and I wish you a pleasant journey.