A: It does! According to CR 608.2b: “The spell or ability is countered if all its targets, for every instance of the word “target,” are now illegal. If the spell or ability is not countered, it will resolve normally. Illegal targets, if any, won’t be affected by parts of a resolving spell’s effect for which they’re illegal.”

Approved by Scott Marshall.  Cards: Searing Blaze

A: “The Song only affects the color of the card (by making it colorless), types that it has (and subtypes that it has), and any abilities it has (and gains the ability to tap for one green mana since it’s a Forest). It won’t affect anything else, like the mana cost of the card. Even if it’s enchanted by the Song, the Tusker’s mana cost is not affected, so it will still provide two to devotion to green.”

Approved by Nathan Long.  Cards: Kalonian Tusker; Song of the Dryad

A: When multiple replacement effects are trying to affect the same event, the affected player doesn’t choose “the order to apply (them)”–instead, they choose one and only one replacement effect to apply, and then the game re-evaluates the situation to see if more replacements are needed. This means that in this situation, AP determines whether to apply NAPa’s or NAPb’s Thief to the first draw. (Let’s call the opponents Alan and Barb respectively for clarity’s sake.)–if they choose Alan’s Thief, the game then re-evaluates the situation. Since Alan is drawing a card and is an opponent of Barb, Barb’s Thief wants to apply, so it does so and Barb ends up drawing a card. And this happens the other way around if the active player chose to apply Barb’s Thief, so in that case Alan ends up drawing the card. In this specific situation, it amounts to much the same thing as “AP gets to choose who draws the card”, but the underlying mechanics are different.

To illustrate the difference, let’s add a third Notion Thief opponent to the mix, Carl, and start again. Now, when AP starts drawing that first card, they need to choose either Alan’s, Barb’s, or Carl’s Thief, and again, let’s say they choose Alan’s. Now the game re-evaluates: Alan is drawing a card, and both Barb’s and Carl’s Thieves would like to apply…but the player affected by those replacements is now Alan, not the active player, so it’s Alan who chooses which effect to apply. (And then, as in the original situation, the player whose Thief Alan didn’t choose winds up drawing the card.) So unlike in the original situation, the active player doesn’t get to decide who ultimately draws the card–Alan does. And adding additional opponents with additional Thieves continues this pattern, each player passing on the decisions to the next until there’s no more decisions to be made because only one effect is left.

Approved by Callum Mine.  Cards: Notion Thief;Brainstorm