I — Create a 1/1 white Mouse creature token. II, III — Create a token that's a copy of target token you control. IV — Creatures you control get +1/+1 and gain vigilance until end of turn.
2023-09-01
If the copied token is copying something else, then the token enters the battlefield as whatever that token copied.
2023-09-01
Only creatures you control at the time the fourth chapter ability resolves will get +1/+1 and gain vigilance. Creatures you begin to control later in the turn won't be affected.
2023-09-01
The token copies the original characteristics of the target token as stated by the effect that created the token.