How It Should Have Ended: Not A Loud.
Yet again, I'm asking the musical question "What if Lincoln Loud weren't a bog-standard Nickelodeon Imbecile Hero born to humiliate himself to make the little boys watching feel more secure?" and using it to improve Savino's attempt to pave over a plot hole.
We find ourselves in the attic of 1216 Franklin Avenue watching Lincoln and Clyde try to decipher a puzzle: the absence of "Baby's First Day" photos in Lincoln's baby album. Since we live in the real world and not a continuum of cartoon fools, Lincoln told Clyde "Well, as they say, 'absence of evidence is not evidence of an absence.' My missing pictures could mean something benign and embarrassing. I mean, Lori and the others were really tiny back then and they might have wanted to see the pictures of their new brother and exposed the film and ruined it."
Clyde said "That might be but I'm not sure Mrs Johnson would accept that as reason for not turning in a complete assignment. She doesn't really know your sisters that well and, well, she's still kind of sore about the egg-sitting thing."
Lincoln agreed that this was the case but then said "Well, what if we can prove something went wrong with the film? Let's look for pictures in the other albums that show a camera!"; to keep Clyde on task, Lincoln looked through the older sisters' albums while Clyde looked through those of the younger ones. Sure enough, each of them had a picture of Lynn Sr's reflection holding up a camera. Actually, two cameras. One camera (the one Lincoln had repaired so he could take a family photo) for the older sisters and another, newer one for Lucy on downwards.
The answer to Lincoln's quandary became obvious to him. So obvious, that he didn't put much oomph into his "Dang it, Dad!"
He then picked up his album and told Clyde "Let's go downstairs and ask Dad what gives, okay?"
A few seconds later, Lincoln walked up to his parents, held up the album, showed them the empty "Baby's First Day" page and said "Who dropped the camera eleven years and change ago? I have to know this so I can explain to my teacher why I have to turn in an incomplete assignment."
Rita and Lynn Sr stared at one another for a second because they'd hoped never to have to answer questions about the first day of Lincoln's life for years to come. Also, this was not the question they'd expected. Lynn Sr asked "Uh, Champ, don't you want to know about what happened then?"
"Not really. I assumed I was born in a hospital like everyone else and one of the girls was so excited to have a baby brother, she'd gotten a bit too happy and wrecked that old camera of yours. Totally understandable because Lori was the twins' age back then."
Rita smiled and said "Fine. You got us. They got grabby and blamed one another for it. Happy?"
"Sort of. I'm in for another incomplete but at least the reason makes sense. Imagine what would happen if I were stupid enough to think that comics were real life?!" before going on his way to his room to finish typing up his report. Since he didn't want to stir up bad blood, he'd decided to not to ask the girls about something that they were still probably kind of sore about.
A few minutes later, Lynn Sr said "Wow. Did we dodge that bullet or what? I don't know what the girls saw back then so who knows what they'd have told him?"
Rita said "You heard the boy. He'd have thought they were lying to cover up a mistake! Practice makes perfect, you know. If he hadn't come up with that on his own, that was what we were going to tell him anyway."