"Except" at the beginning and end of a sentence

[Rachel Adams]

Why is "for" required in sentence #1 while in sentence #2 it is not required?

1."Except for Anna everyone was ready."

2. "Everyone was ready except Anna."

 

[emsr2d2]

It's optional in all of them.

Except for Anna, everyone was ready.
Except Anna, everyone was ready.
Everyone was ready, except for Anna.
Everyone was ready, except Anna.
Everyone, except for Anna, was ready.
Everyone, except Anna, was ready.

 

[GoesStation]

Except Anna, everyone was ready.

That one doesn't work for me. All the others are fine.