So, in chapter 6, Cristopher freaks out because he saw his universe's version of an infamous comic, and depending on your opinion, it can be quite funny. However:
How did he found out about it? Surfing the internet would be the logical, even obvious, answer, but there's still the matter of how did he found about its existence...
Assuming it's the same as the normal dimension, the comic isn't exactly easy to find. So how much did he dig in order to find it?
What else did he see on his way to the comic? Assuming the above is correct, then he would have to look around the internet in order to find the comic, and it's very likely he would probably find something even worse by accident...
Chapter 14 confirms Chris indeed found more disturbing Loudcest fiction, including a story about Linka and her brothers ending up being the last people on earth, forcing them to "breed" among each other to repopulate the world. And he doesn't like it one bit.
It also confirms how he's finding all of it. He's not even 'trying' to find it.
Linka, in Lincoln's body has convinced his sisters that he is transgender 'and' is attracted to Clyde. Lincoln eventually hopes to reclaim his body, but what kind of life will he be returning to?
Chapter 11 elaborates on this: so far his family will think he's transgender and he'll be dating Clyde.
And in Chapter 12 it officially becomes Ascended Fridge Horror when Lincoln himself points out to Luke how Linka has pretty much ruined his life during the time she's been in his dimension posing as him.
Though, chapter 16 shows it may not be as bad as we first thought. Linka has started to change as well.
After Trevor was defeated, he released the anomalies he captured, by what the author describes there were hundreds of them and now, they've been released!
Luke and Lars are the only brothers to discover Linka is trapped in another dimension and has no intention of coming back, and they took it pretty darn hard. Just how much harder will the rest of the brothers take it when they discover the truth about their sister? Heck, how hard will the parents take it?
Going off from this, Luke seemed to be ready to beat up Lincoln for not telling him earlier. What will the rest of the family do to him?
When you think about it, once the truth does come out, Lisa will be in a living hell of a punishment.
As of Chapter 20, Lisa, Lola and Lana know the truth. One can only imagine what Linka, who wants to keep Lincoln from coming back at any cost, will do if she learns that 3 of "her sisters" are aware of what is going on.
In universe. When defending her actions to Loki, Lincoln points out that any number of other versions of Lincoln Loud might have swapped bodies with Linka other than him. Bringing up the notions of murderous or suicidal Lincolns.
In chapter 37, 11B Lincoln's reaction to the girls fussing over him like they would their original brother is to blatantly wonder if this is what it feels like to be loved. That's right; his brothers' bullying made him feel completely unloved. Seriously; what the Hell, Lynn Sr. and Rita of 11B?
How was Lincoln able to connect a duel disk to a motorcycle?!
What in the living heck is Lisa doing during all of this?! Her brother not only completely changes after his trip to the other dimension, which she only sees as slightly suspicious and not more, but she completely fails to think about the possibility that it's because of the gadget she made that her brother changed so suddenly?!
Why did Lincoln take Luke to her room in chapter 13? Because when talking about her life, Lincoln mentions that her room's walls are thicker than the rest!