I was going to reply to this last night but I got sidetracked.
Okay. First off, I like your warm palette and your olive greens. Nice move there. I also like the texture on Thing, and your gold rendering.
Now for the stuff that needs critiquing. You've got some confusion going on with values and saturations. When you're dealing with a limited color scheme like this hazy yellow scene, you've got to prioritize your areas of overlapping similar hues (like yellow sky, brownish-yellow pyramids and yellow on costumes) into a way that best serves the storyline.
Panel 5 is kind of a mess overall, because there's this whole area in the center that gets very muddy and unclear. Wolverine and Pixie's suits are muddy. Their skin tones are muddy. The pyramid in the background is kind of a mud color. Even Pixie's hair is dull and purplish...and all this under a hazy yellow sky? If you want to create depth, you definitely need to break up that whole area right in there. And if you want to enhance the storytelling...
Pixie, Wolverine and Thing should attract the eye, even in a limited-palette scene. Think about this: The X-costumes are YELLOW and blue-black. Not ochre, not raw sienna, not maize or honey. YELLOW. Under a warm sky like this, you KNOW they would appear as the yellowest yellow that ever yellowed. But the colors you've chosen for Pixie's and Wolverine's suits AND skintones are pretty much exactly the same values, and are very close in hue, to the pyramids and flying rocks. I miss Wolverine almost entirely in panels 3 and 5, and if it weren't for her pink hair, Pixie would disappear against the background in panel 5.
So now comes the pushing and pulling of the values and saturations. Without telling you the step-by-step of how I did this, I'm just going to post your version followed by my version, and let you spot the differences. The point is, you can stay true to the limited palette and the atmosphere that you want, while still adhering to the storytelling and visually separating everything. I hope that makes sense!