3 users on one account

So what you could do is setup 3 different accounts, as there is no way to setup 3 different users on the same account,

https://support.xbox.com/en-CA/help/hardware-network/getting-started-set-up/connecting-to-xbox-live

In this article it also shows you how to share gold.

I hope this helps.

Exactly. Once you've added both accounts to the new console simply add the Gold membership to your account then head over to Settings on the console (say "Xbox Go To Settings) then scroll right and add your son's (and any other family members) accounts
to your Family so they can enjoy the benefits of a Gold membership as well.

Xbox can't provide email information to users.

Reason is because people attempt to gain other's email info through this route.

No thats not possible. 1 Microsoftaccount & 1 Gamertag = 1 Profile. Membership, Gamerscore, Achiefments, Savegames are also bound on 1 Gamertag.

Many thanks for the information. Just what I was after.!