What happens if all my characters are tapped when I play Swap Missions?
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?
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 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?
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.
The first suggestion is correct in this scenario.
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?
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.