Dunno why I never thought of this, but I just read about how Ike can avoid Marth’s Counter on the edge. Usually Ike goes to Aether, Marth does Counter and smacks him away because the super armor wears off after he grabs the sword.
But all you have to do is reverse the Aether. When Marth Counters an Aether that’s turned around, Marth turns around as well, leaving Ike to safely grab the ledge instead of getting smacked by Marth’s sword.