After Atlas settles down the female bodyguard down to the bed that Lina previously made inside the cottage, I resummoned Leona to fetch the two bodyguards and the researchers who are left behind on that small island where I found the Eternal Ice and the Sea Worm who devoured it. Although my point of going to Aquagius is to learn more about the girl in the photo which ended up being fruitless, it still didn't end up as a fruitless endeavor for me as I managed to secure the Weapon of Greed out of pure coincidence that I didn't expect it to appear just like that.
Anyways, it only took a few minutes for Leona to return to the little island. This time, I didn't go into the forest again and directed Leona straight to the area where everything happened. By now, the bodyguards should already have seen Leona especially since I used her the moment I fall down the hole to chase the Sea Worm.