How many Xbox Live subscriptions do I need?

Actually, both Daft Badger and M3tal Daz3 have a point. What M3tal is trying to say is that what if player C wants to play on console A. Since player C does not have gold and the home xbox feature is only shared on his console, then he won't be able to play
online on console A since no gold has been shared there.

What Daft is trying to explain is that if Player A don't intend to allow Player B and C to play on his own console. That's where you will only need to gold accounts. I hope that's more clear to understand.

Well we seem to have some conflicting information. So is it two or three? Thanks again.

The Op cleraly stated "I have 3 Xbox One consoles in my household. Mine and one each for two of my boys" That makes 3 xbox consoles that he wants to connect on xbox live.

How can the OP use only 2 gold subscriptions for 3 xbox consoles?!

Daft Badger I suggest you to read better the conditions of using home with gold:

support.xbox.com/.../xbox-live-gold-sharing-features

Defence just so you know that once you sign in an account to a console, and then it will be signed in again to another console, the profile from the 1st console will be signed out automatically.

So if you want to use 3 consoles contemporaneously in live with 3 accounts you need 3 memberships!

Daf Badger so how can the third console be used on live at the same time if the third profile is yet in another console?