Not clear enough but I'll try and answer anyway.
Warden can give a Simon says order without starting Simon says at all however I wouldn't expect reds to follow the order because warden is intentionally trying to trick them with nonsense for no reason so I would punish them for killing reds for breaking the "no trick orders" rule.
For the second question, if the warden starts Simon says, they do not need to specify they are Simon nor does Simon need to say "Simon says is now over" when the game is finished, warden overrides that as warden is the only person allowed to give orders.
"Upon announcing the game, the warden is now Simon and orders given shall only be followed if they are prefaced with 'Simon Says', otherwise they can be ignored. Announcing the game's end is done as the warden, and does not have to be prefaced with 'Simon says' either."