Also: better now than later. Surely it'd be much easier to tell them while they're new and don't know how the architecture affects everyone there, instead of letting them carry on for six months, while you fume and are unhappy, and become wearier and wearier, with your nerves more frayed from lack of sleep, and only THEN telling them.
If you find them receptive, you might invite one of them downstairs into your appartment and ask the other to do whatever he/she usually does each morning. Remember that this will most likely sound less noisy at any other time of the day (and is probably best done at that early hour), but even later in the day, the neighbour standing in your bedroom with you might be able to identify the specific sounds. That way, they wouldn't feel they have to tiptoe around for every single sound, but only for those which actually disturb you. Perhaps they could, e.g., not slide the cupboard door or could perhaps boil the breakfast kettle in the living-room, whereas they could feel free to use the electric toothbrush and to shower... etc., etc., depending on which of those sounds carry.
Another idea might be to consider swapping rooms with your son. If the neighbours' noise doesn't keep him from sleep, and his room is further from where they're busy in the morning, perhaps you could permanently live there and move him into your current room.
There's a Swiss expression "Fuscht im Sack", which means clenching your fist in your pocket. It is what people do when they try to swallow down their annoyance. Please don't do that to yourself, nor to your neighbours. All too often, when the pressure and anger have festered too long, out comes that fist (metaphorically speaking) and does someone some damage.
I'd like to encourage you to deal with this issue now, to clear the air so you (plural) can start the New Year happy!