Yes!
No, after the battle, you check, and the upgraded character is not the one who attacked, so it would not scrap itself.
Sabotaged Armaments is revealed when one of your characters defends, before Battle Cards are flipped. Power Punch will be scrapped before it can affect that battle.
Optimus Prime - Battlefield Legend is equipped with Power Punch, flips completely for his attack, and chooses
Leap of Faith as his Action. The first card Leap of Faith reveals is
W-5 Gyro Blaster. If OPBL attaches this, do I keep all the flips revealed from Power Punch? If so, does that mean my opponent now cannot flip more than 2 cards for their defense now that W-5 Gyro Blaster has been attached?
[Source: WotC]
No,
W-5 Gyro Blaster’s ability only triggers if it’s attached when the character attacks or defends.
No. This all happens before Battle Cards are flipped.
Speaking of which, what happens when a character upgraded with
Anticipation Engine swings into a
Sabotaged Armaments?
Anticipation Engine and Sabotaged Armaments will both trigger at the same time. The attacker will resolve Anticipation Engine first, then the defender will resolve Sabotaged Armaments.
The
Grenade Launcher will be scrapped after battle. This is in contrast to
Fusion Borer, which would stay on
Cerebros after the attack.
This is due to a change in language as the game evolved. Early on, WotC used language like "After the upgraded character attacks -> Scrap this card.". Later, they adjusted to "When the upgraded character attacks/defends -> Scrap this card after the battle.". This newer language ties the scrap to the more common "When battles" trigger and not to the rarely used "After battle" trigger".
The same is true for other older cards like
Evasive Maneuvers,
Blast Shield, and Power Punch, vs newer cards like
Emergency Barricade and
Crystal of Power.