I don't believe XC1 is a "full-on remake". At its core, it's still the same Wii original game. Cutscene animations are a match, the biggest differences are the facial expressions showing more emotions to work with the new designs. The combat doesn't feel or play that much different from the original outside of some QoL updates and balancing. Contents, areas, enemy placements, etc. are pretty much the same with a fresh coat of paint.
I believe XC1DE is as much of an enhanced remaster as XCXDE is.
Remakes tend to match choreography as it is. It's not meant to be a reimagining. But even then, those are just a small piece of what went into XC DE. It isn't simply having better character models or facial expressions. They went through the whole shebang, including the environment geometry and texturing. That's the whole point of a remake, and don't let SE tell you otherwise.
At no point could the original engine on Wii be used or even ported over to Switch. It's not simply a difference from AMD (or ATI at the time) to Nvidia. It was literally on different sides of the technological divide. Just on the GPU side, it's going from a fixed-function pipeline to a programmable one. In this case, the transition was from Wii to Wii U. So they had to redo that. The difference to get XCX running on Switch 1 is not nearly as drastic because the devs were already working with a programmable design, and essentially, the same engine to an extent.
And that's the thing. XC2 is built on an updated engine for Switch that XCX ran on for Wii U. XC DE ran on an updated version of that engine. Then XC3 the same way, all the way until we get to XCX DE. It's essentially running on an updated engine of what it had used before.
This is why, technically, the XCX version is the oldest of the Switch XC games on a technical level, even if it was the last to be released on the system. Because it's an enhanced port from Wii U, not a remake. What makes it special and perhaps troublesome is just how vast and "open-world" it is. The devs weren't remaking the game, but they did have a lot of data they had to deal with.
That is why I drove the possibility of the other games not having a higher cost, because they are all essentially derived from what was done with XCX, perhaps on an even lesser scale for not being open-world.