There are spoilers, so proceed at your own risk. Building a Batfamily with an older Bruce and a younger Superman; an unconventional cosplay transmigration story, set in a still-unofficial AU.
"Father, don't you think our lineup looks just like the Batfamily?"
When the kids blinked up at him with hopeful eyes, Bruce knew it was over.
There was no way he could refuse these adorable little ones, so Bruce sighed and put on the Batsuit.
It was just a comic convention. He'd go. He'd throw himself into it.
Meanwhile, Clark was thrilled to learn that his crush was going to cosplay Batman.
Hoping to get closer to his crush, Clark, still a green newcomer to the DC fandom, turned to his seasoned cousin for help. His evil fanfic-loving cousin then gave him a crash course in the story.
Unaware that her explanations had included some personal embellishments, Clark immediately decided to cosplay Superman, Batman's love interest.
Then they all met at the convention. The cosplayers squealed and took pictures together, the visitors squealed over how accurate their costumes were and took pictures together, and the Wayne and Kent families squealed as they transmigrated.
Theme: Love and hate are tangled up in one "foolish" word.