saying the Emergency Declaration is legal and Individual 1 was right to do it. So, just another corrupted person in an important/crucial office

That's their job (the Solicitor General would probably handle it, not Barr himself). But I'm sure Spanky wanted him there to make the point.

Even if there are a lot of claims that "this is illegal" or "that is legal" based on the claims of politicians, lawyers, and advocates.

As long as it's what we want to hear, the obvious isn't pointed out. (Although, to be honest, it's more important to point it out when we really want to believe and accept the politician, lawyer, or advocate as speaking the purest truth than when it's somebody we loathe and distrust. We're less likely to self-deceive with the latter than with the former.)

was his big chance to show everybody who he is.

He auditioned and got the job

Do all these people meet in a room before ceremonies where they are given their lines and rehearse them?

Time to pay the Piper.

Acting like a suck-up.

Telling Individual 1 how right he was and within the law to make the declaration. The only thing missing was his hat in his hand.

And on a side subject, why is it that the 'cowboys' he often has around him never remove their hats in the Oval Office?

It was pandering to Trump, and offering protection.

Sickening.