If I play Stand Your Ground and it gets cancelled does the character lose the honor token? The way the card is worded makes the loss of the honor token not sound like a cost. But it could definitely work the other way.

I would agree. Costs are always up front with effects for those costs afterwards. The cost system could use some improvement in its design though.

If it's before the dash, you'll pay the cost regardless of if it gets interrupted. If it's after the dash, that's upon resolution of the ability and won't happen if the effect doesn't initiate.

This is a replacement effect, so discarding the honor token is replacing discarding the honored character. If the replacement effect is interrupted, then the character is discarded following normal rules, and you gain 1 honor for its honored status.