What happens if all my characters are tapped when I play Swap Missions?
[Source: WotC]
First you’ll untap one of your characters. Then, because that will be your only untapped character, you’ll immediately tap it.
What happens if all my characters are untapped when I play Swap Missions?
[Source: WotC]
Playing Swap Missions in this case is probably a bad idea. Because all your characters are already untapped, you can’t untap any of them. Then you’ll tap one of them.
If I use Swap Missions to untap a tapper character and then tap an untapped character, and that same untapped character has a tap ability – does Swap Missions trigger that tapped ability?
[Source: WotC]
No, tap abilities (ones with the tap symbol) happen when the player activates them on their turn and don’t happen if the character is tapped in any other way.
If I have a Micromaster in Bot mode, and I use an action that taps it, such as
Inferno Breath or Swap Missions, will tapping it with one of those actions let me activate the Micromaster's Tap ability?
[Source: WotC]
No. Those are mutually exclusive. Tap abilities on Micro Masters are costs for triggering their abilities, so other in-game actions do not allow you to use that ability.
I have
Optimus Prime - Battlefield Legend and an untapped partner bot on my side. I attack with Optimus in bot mode. One of his flips is Swap Missions. If I elect to play Swap Missions, Optimus untaps and my 2nd bot taps. What happens next? I argued Optimus was still the attacker even though he is untapped, so combat with him should proceed. My opponent argued the other bot was now the attacker since only a tapped bot can attack (since the two "swapped" missions), then utilizes the earlier flip's battle icons.
[Source: WotC]
The first suggestion is correct in this scenario.