OP - Good luck with car, sounds like a nice one.
My limited experience with new Mazdas to my family seem to show high moly in their oil and the undercoating a good idea. The first OCI is a dilemma. Virgin oil analyses show Mazda oil contained Manganese - a scuffing agent. High molybdenum content you can find in modern oils, but I haven’t seen shelf oil with any manganese. ( A good thing imho)
So an early dump of the ff might not work as well as hoped. If you can get Mazda data that is current, it might help you.
Honda used this procedure for a long time and they were adamant about NOT changing early.
Dont know how much this helps, but either way, enjoy the car. Earlier references to this choice were well said in this thread, so reread and let us know what new data you find.