On the other hand, the “skill” category seems to include “assembling a working battlemech out of balloons in seconds.” So I’m not sure where the limit is, really.

actually this is a really good question, who’s narrating this ?

is it echo ? mustard ? is it mustard misremembering because of echo ?
is it an omniscient narrator ?

As far as we know, she has Gus’ silver tongue not only in a figurative sense…

Yeah this makes sense. Ringmaster’s Routine is a skill, not some magic mental nonsense. Misrepresenting things, skewing people’s memories of a situation, convincing them of falsehoods…something entirely unbelievable is, well, unbelievable, but if he can make something convincing enough, use your own memory against you and skew the facts or sell a lie, then his manipulations will stick. Maggie copied that manipulative skill from him, that explains why she had her mouth sewn shut: Gus knew she could do what he does, if she wanted to. So he prevented that, without irreparably damaging her as an asset, by rendering her unable to speak.

Exactly. Maggie copies skills, and Gus’s ability to manipulate others is a skill. He was established as amazing at tricking people into believing certain things, damn good at twisting a conversation and making you think what he wants you to think about a situation.

What I’m wondering, honestly, is how the hell he had her mouth sewn shut. Echo was an absolute monster in combat, she can’t copy clowns who rely on inherent attributes of themselves, but anything reliant on skill or training is fair game. My theory is that he convinced her to do it herself, because there’s no way in hell he pulled that off against her will with her skillset and arsenal.

But what about all the other characters who’ve had black-and-white flashbacks/memories? McBell, Ollie, Bout, Fuchsia…

In fact, as far as I can recall, Morgan/Mustard is the only character who’s had an full-color flashback, and that was also the only flashback that was later contradicted by a different flashback.

I think both are true actually. I think Maggie is presenting a false narrative of events and that Morgan was a jerk in high school. That’s why Maggie’s lies are even working because there’s a hint of truth. Oats/Livewire even told us that Gus’ ability works better if there is truth to it. We even saw Maggie tried blatantly lying in this fight about Fuschia betraying the Clown corp and Mustard didn’t fall for it. So Morgan was likely a mean girl, just not an evil cheerleader that chucked people around like dodgeballs.