Game pass ultimate tied to console?

The subscription is not tied to the console. You still need to redeem it on an account. If you did not do so during setup of the console, you can redeem it from that section you mentioned.

Xbox Game Pass Ultimate can be used on Xbox One, Windows 10, Android (Cloud Gaming) & Xbox Series X|S The subscription is tied to your account, not the console.

It's legit. That was never tied to a promotion or a limited time thing. As long as you are going from standard Gold or Game Pass to Ultimate, it will upgrade at a ratio of 1:1 (Adding standard Gold or Game Pass to Ultimate converts at a different ratio).

The ability to play games through the cloud is not determined by any console type. It would be determined by your subscription. If you have a Game Pass Ultimate subscription, you should be able to play via the cloud on either an Xbox One generation console or on a Series generation of console. It is tied to your account not the console type. Do you currently have an active Game Pass Ultimate subscription? Please note that sharing of Gold through the Home console settings does not enable cloud gaming. Cloud gaming is only available to the actual account with the subscription.

No. The upgrade is not tied to any promotions or only for new members. Anything you have a standard Gold or Game Pass subscription and then you but Ultimate, it will upgrade what you have to Ultimate at a ratio of 1:1.