What do you mean by use chandra and copy
make mischief? Also, you would need 8 creatures and mirrorwing already out on the field (meaning you're probably winning already). Then the 4 devils die, dealing 4 dmg. 9 devils are created, but they can't immediately
deal damage. Unless you mean create a bunch of devil tokens and minus chandra to wipe your own board? That seems fine but the issue is in running
mirrorwing dragon in a meta with marvel.
Harnessed lightning gets copied for each of the marvel players creatures (
whirler virtuoso) giving them essentially infinite energy. Maybe out of the sideboard against zombie decks, but the risk is too high against
harnessed lightning.