Multiple subs on one account

[Eldevern]

From what I see, you can have several "service account" and for each account several platform licences (PC/Mac/PS).

So, it seems :
on one "global account", you can register several "service account".
on one "service account", you can register several platform (though you need to purchase the platform-specific licence of the game for each platform)

Characters from one service account will be shared between platforms but not between the two account services.

But in my opinion, you should better keep two totally separated accounts. It will be less confusing especially if one day you stop using a one of them.

In other words, it looks safer to do :
Global A - service A - Licences PC/PS/Mac whatever available
Global B - service B - Licences whatever you want

Rather than a mix
Global A - service A
Global A - service B
where you could end by setting the wrong licence on the wrong account.

Plus, if you play with your son, to keep global accounts separeted will allow your son to manage his account when you will think he's responsible enough to do so.