Since we're trying to get exactly how Sakuretsu Armor works, let me explain the Moot point.
Player A'sGemini Elf attacks.
Player A passes priority.
Player B activates Sakuretsu Armor. Sakuretsu Armor looks and sees the attacking monster, at now is aimed at its target. It know it has to look for that specific Gemini Elf to destroy.
Player A doesn't chain
Player B chains Magic Cylinder. Gemini Elf is identified.
Player A doesn't chain
Player B chains Draining Shield 'I'. Gemini Elf is identified
Player A doesn't chain
Player B chains Draining Shield 'II'. Gemini Elf is identified
Now let's remember the card texts
Draining Shield
"increase your Life Points by the
attacking monster's ATK."
Magic Cylinder
" inflict damage equal to the
attacking monster's ATK"
Sakuretsu Armor
"Destroy the
attacking monster."
All say attacking monster, and all are targetting effects.
We already have a ruling for Draining Shield:
http://lists.upperdeck.com/read/messages?id=1766
So we resolve in reverse order:
Draining Shield 'II' Negates Gemini Elfs attack and increase Player B's life points.
Now Draining Shield 'I' resolve. Now Gemini Elf is no longer "attacking," yet the ruling above shows that it still can increase the player's Life Points. Why? Because it has already identified Gemini Elf as its target, it's no longer looking for an attacking monster to identify.
Magic Cylinder resolves. Gemini Elf is no longer attacking, but that doesn't matter, as it has already identified Gemini Elf, and will now inflict damage.
Sakuretsu Armor resolves. Gemini Elf is no longer attacking, but that doesn't matter, sakuretsu armor has already identified its target.
So as long as Sakuretsu Armor's target is identifiable, it doesn't matter whether its still attacking or not.