My opponent declare a Night watch as an attacker, with standing Jon Snow, who will auto participate in the challenge:

Highgarden

Q1 could I trigger Highgarden to remove Jon Snow?

(My point is if I could not "stand" a stand character, is that mean I could not trigger this card?)

Q2 what if I use Highgarden to remove the Night watch character?

Will Jon auto leave the challenge? Coz no other Night watch is in the challenge.

Aero Hotah

Q3 if I ambush Aero Hotah to remove Jon Snow, will Jon automatically jump back into the challenge? Coz he is still stand.

Q4 similar to Q2, what if I remove the Night watch character?

Tks a lot

1) With Highgarden, the standing and removing from the challenge are independent (neither is a cost, and they're not linked by a "then"). So if at least one can happen, you can trigger Highgarden. However, removing Jon Snow from the challenge doesn't do anything either, since his ability is still applicable. That means you can't trigger Highgarden on Jon Snow, because it would have absolutely no effect.

2) If you remove the other NW character, Jon Snow's ability becomes inapplicable, so he no longer participates in the challenge.

3) You can't trigger Areo Hotah's reaction on Jon Snow, because it would have no effect.

4) Same as 2.

Khudzlin, as usual, has it right.

Keeping sharp for this weekend

Thank you