Removing a creature from combat doesn't change the fact that it attacked, even though it's no longer an attacking creature. Notably, raid abilities will still be satisfied if every attacking creature is removed from combat.
For more information on double-faced cards, see the Ixalan mechanics article (http://magic.wizards.com/en/articles/archive/feature/ixalan-mechanics).
There are many important moments in the story, but the most crucial—called "story spotlights"—are shown on cards. These cards have the Planeswalker symbol in their text box; this symbol has no effect on gameplay. You can read more about these events in the official Magic fiction at http://www.mtgstory.com.