@Kasey-Snow beautiful work!
Yes, the one in the upper left corner does stand out as different from the rest. Making it more cohesive with your current style is a good call. Lightening up some of the darker pieces will also help with the readability.
Regarding the web comic: you might want to keep that out of your portfolio. It looks a little more mature for MG/graphic novel and the style is slightly different.
The illustration on the bottom left corner is difficult for me to read. Is it a dragon and —something else— hugging? Or are they fighting? Why are they in the sea? It might just be my eyes, but that one confused me.
The Moonflower does need a little more work; I agree that there’s something about it that isn’t quite hitting how you’d like it to, I think. Could you crop it a little more so that the character is larger? Move them up slightly, as it looks like their bottom is resting on the bottom of the page?
I love the illustration of the cougar(?) in the cave and the one of the horses on the far right. Even though it would be improved with updating, I do love the storytelling of the one in the upper left corner. Again, gorgeous work!
Please keep us posted how everything goes.