I really like that Jacobean/classic grey. Its possible they mislabeled the sample but more likely that the planks just took the stain differently. Wood flooring is a natural material and so not all planks will look exactly the same even with the same finish applied. Some planks are naturally darker than others.

Liana , in the last photo second from right. If thats the color you are considering maybe have one more round of samples made using several planks of varying natural color.

What do they look like in the same amount of light?

Hard for me to tell....is the island a darker gray? IMO, the bottom picture of your OP to the far right reads too red. But again, I'm not looking at them like you are. I would not lean red though....

Dural Seal/Minwax stains will lighten up a lot after they have dried. Adding finish will bring the color back to what they would have looked like when being applied. It doesn't look to me like there is any coats of finish over the stain yet? Depending on the finish being used (water based, oil or solvent base) this can darken a little or a lot and even change the color tone once the finish is applied. Don't make your final decision without finished samples to choose from, at least one coat of finish anyway.

The Jacobean over a red oak floor will tend to throw some red tones especially over boards that are very red naturally. If your mixing with the classic grey and don't want any red tones coming through I would suggest mixing it with the Espresso or even Antique Brown to darken the grey stain. These colors won't darken the open grain as much as Jacobean, Coffee or Ebony.

If you have a color you like but want it darker have them water pop the wood before staining but make sure it is completely dry before adding stain. This will help to give a more uniform appearance and will come out darker than staining without water popping.