What is the best way to setup accounts, purchases, allowing others to play on my console...

check this link Set Xbox One to Home Console

https://support.xbox.com/en-US/games/game-setup/my-home-xbox

If someone signs in with their account information on your console they have access to everything they have purchased its that simple. FYI kids don't accidentally hit buttons and there is a confirmation after choosing to purchase an item. Make sure your
kids are on a "child account" and you can restrict things they can do.

You may want to just remove any persistent payment information; this means youj will have to enter it every time you make a purchase though.

Definition of a Microsoft child account

How a child account is defined

At Microsoft, a child account is defined as any Microsoft account that’s affiliated with an adult Microsoft account when the age of the child or teen is less than the age of majority for his or her country. When this is the case, the child must be linked
to an adult’s Microsoft account in order to participate in the Xbox Live service.

When it comes to managing a child’s privacy and online safety, Xbox One breaks the definition of “children” into three categories:

• Young child: Anyone under the age of 8
• Child: Ages 8 through 12
• Teen: Ages 13 through 17 (or 19 in South Korea).

Related Issues
Add a new member to your Xbox One family

Manage privacy and online safety for Xbox One

https://support.xbox.com/my-account/security/create-xbox-one-passkey
Hey there Tech thanks for taking the time to bring these questions to us.

We apologize for the confusion this has caused but rest assured we are here to help. We will be breaking down these inquiries into several answers to be as clear as possible.

First things first, the way to share the console would be to set it up as the
Home console, this will allow other people to add their account to the console. Check out our Home console page for more information.

Second, check out our
Prevent unauthorized purchases by children on Xbox One page to see how to prevent unauthorized purchases being made.

What should be done to prevent the charges in the future is
setting up a passkey and select either ask for my passkey or lock it down permissions.

Check it out and let us know if we can further assist in this or any other issues!

A gold subscription is what allows you to play online. You would need at least 2 gold subscriptions for 3 consoles. Gold is tied to the account that purchases, not the console. The Home setting allows an account with gold to share their gold with other
accounts on a console. So you could buy gold on 2 of their accounts, then have one of them set the 3rd child's console as their Home so the 3rd can have gold as well. https://support.xbox.com/games/game-setup/my-home-xbox

Hey andrebosseau,

If you those games were purchased via your son's account, he would have to set the console you have as the "Home" console. This allows him to share gold as well as any games he purchased with other users on the console.

More info on home Xbox settings: https://support.xbox.com/en-US/games/game-setup/my-home-xbox

Best,

Nozzle