I wanna reiterate that we gotta keep a few things in mind regarding K. Rool's reveal: it premiered at the end of the Direct, to close the presentation. Leading up to his reveal, we'd just gotten a ton of info on new stages, music, interface options, characters, items, ATs and game modes, so to look at K. Rool's trailer and go "Well I didn't see Dixie so clearly she's done" isn't the best conclusion to draw. Since the K. Rool trailer dropped without a follow-up overview from Sakurai, we need to wait until the next Direct to get a better idea of Dixie's fate.
Just as the Inklings got announced months before their overview, it seems that K. Rool's getting a similar situation. When the next Direct is up we'll get an extended look at how the Kroc plays, and if she's an Echo, Dixie's best shot at being revealed will be as an "oh, BTW..." during K. Rool's spotlight. If she's not an Echo she's certainly getting a segment to herself to show us away she can do. Overall, as a way to close the Direct and keep us speculating, K. Rool's best off with a trailer focusing on him, as he's been fiercely requested and gone for 10 years, and the results speak for themselves.
As for the Klaptrap AT, that doesn't deconfirm Dixie, it foreshadowed K. Rool. He has a stronger association with them, being his underlings after all. Using that to deconfirm Dixie when it means K. Rool had an indirect presence seems like some people are jumping the gun. A Dixie AT would deconfirm Dixie. A Kong AT would foreshadow a new playable Kong, which includes Dixie indirectly.
Another thing worth pointing out is that if they're both in the game, they're in for 2 different reasons. Fanservice is what got K. Rool in Smash, as he's been dormant for 10 years, and that's absolutely great. If Dixie's in, she'll be riding in on Tropical Freeze, as SSBU's era of games will focus on Wii U, some 3DS and a couple of Switch releases in addition to fan requests. Basically 2011-2015, with some exceptions. Of the 4 Unique characters, and all the announced Echoes besides Richter, the Inklings are the only one who don't simply have massive fan appeal. They come from the Wii U era in addition to being fan favorites, and so far we've seen next to no newcomers that are a part of the era of games that SSBU would be focusing on besides them. Dixie would do just fine in this regard, as Tropical Freeze is from the Wii U era and within Smash's focus range this time.
Now, unto the Echo Issue. We know it's possible, but our biggest issue is that--as some users have proven--this is what some believe is all she'll get, that's all she's good for and Unique is completely unreasonable. This is an assumption she's faced throughout most of her speculation lifespan; it's not new, it's just got a new name. We see her merits and ideally we'd like her to be Unique, and some semblance of Semi Clone is fine too. We also know the chance of Echo is there too, and we won't be thrilled but we will accept it as this game looks amazing already. However, we won't pretend like Unique is something that could just never happen either. We see the potential and we're gonna speculate on it.