Stumped

Stumped on a free hit

Not out. The keeper can't stump you on a free hit — not even if the free-hit ball is also a wide.

• On a free hit the striker can only be out in the ways allowed off a no-ball: run out, hit the ball twice, or obstructing the field (ICC 21.19.2 and 21.18).
• The ICC condition says so directly: this applies "even if the delivery for the free hit is called Wide" (ICC 21.19.2).
• If you're out of your ground attempting a run, you can still be run out.

Not a Law: Free hits are an ICC playing condition, not an MCC Law. In a local match there is a free hit only if the organizer says so; without one, the ball after a no-ball is an ordinary delivery.

Source: ICC T20I clause 21.19 · MCC Law 39

Stumped off a no-ball

Not out. You can't be stumped off a no-ball — and the keeper can't run you out instead unless you were attempting a run or another fielder was involved.

• Off a no-ball, neither batter can be out except hit the ball twice, obstructing the field or run out (Law 21.17). Stumping needs a ball that is not called no-ball (Law 39.1.1).
• Law 38.2.2.2: on a no-ball, a striker who is out of their ground but not attempting a run is not out run out when the keeper breaks the wicket without another fielder being involved.

Source: MCC Law 21 · MCC Law 39 · MCC Law 38

Stumped off a wide

Yes — you can be stumped off a wide. The 1-run wide penalty still counts.

• Off a wide, a batter can only be out hit wicket, obstructing the field, run out or stumped (Law 22.9).
• When a striker is stumped off a wide, the one-run penalty stands (Law 39.4).
• One exception: if that wide's penalty run wins the match, the match is over at once and a stumping is no longer possible (Law 39.4).

Source: MCC Law 22 · MCC Law 39

Keeper breaks the wicket while the striker sets off

It's a run out, not stumped. Stumping is only for a striker who is out of their ground WITHOUT attempting a run; once they set off, it's a run out if the keeper breaks the wicket while they're out of their ground.

• Stumped requires that the striker has not attempted a run (Law 39.1.1).
• A striker not out stumped may still be out run out if its conditions apply (Law 39.3.2, Law 38.1).

Source: MCC Law 39 · MCC Law 38