Changed my account pass. multiple times, but dude can still log on.

What you are describing as having done is actually against the Code of Conduct and exactly why you are not supposed to share your login information / account with other people. On Xbox.com in the "My Account" section, there is a 360 Protection section where
you can force other consoles to redownload your profile before they can use it. I don't believe that Xbox One has anything similar yet.

I have logged into Xbox and Microsoft multiple times, updated my information, changed my password multiple times and still can't download my profile back. I'll keep trying, but here's hoping someone can figure this out.

No, you cannot use your game pass ultimate on 3 Xbox consoles at the same time. For starters, you cannot log in on the same account on multiple Xbox consoles at the same time.

What you can do is share your game pass ultimate subscription on one console, by setting that console as the home Xbox. Once you have done that, then anyone using the Home Xbox can access the game pass ultimate subscription without having to log in with
the account that has the subscription.

You can still log in with the account that has the subscription and play your games and access gold as much as you want on any Xbox, and your son can use his account on the home Xbox and access the subscription on there.

For more info on the Xbox Home setting have a look here.
https://beta.support.xbox.com/help/hardware-network/console/my-home-xbox

Yes I have, multiple times actually but I still got hacked. Unfortunately even when I change my password, it doesn't log ME out of the minecraft launcher.

still no changes) can not even log into my account)