If there are additional costs to cast an artifact spell, or if the cost to cast a spell is increased by an effect (such as the one created by Thalia, Guardian of Thraben's ability), apply those increases before applying cost reductions
This is a very minimal difference between the two categories of cards, but it is an undeniable upgrade
Loxi: At face value and nothing more, it's a 6-cost board wipe with a bunch of random extra value tied to it
If Teval's Judgment's ability triggers more than three times in a turn, no mode can be chosen for any instances of the ability after the third, and those will be removed from the stack and do nothing
Whether your opponents choose to stall and not play noncreature spells until Mystic Remora is gone or bite the bullet and let your draw a bunch of cards, youre pleased with the exchange