Hopefully one of the wood flooring guys will address your questions.

I can't answer your technical questions, but I like the sample right next to the one you circled because it's a warm brown.

Yes, it needs to be water popped, regardless of which shade you decide to go with, light or dark. You may want to try using pinkqualizer, pink blocker or red out with the stains. You do not need to water pop with these treatment.

Early America, Special walnut and Provincial will bring out more red. Jacobean and ebony has some green.

The only two I don't like is the one in the middle and the circled one. I don't like the gray undertones. 2, 4, and 1 look good.

You can't tell what color it will end up if you haven't applied the finish coat(s) to your samples. Samples must be treated exactly the same as the final finishing schedule, including all sanding and finishing steps, to really tell you what you what the color will end up. Doing otherwise results in bad surprises, the changes can be quite dramatic.

If you're seeing too much red then add a dye or toner coat with green in it.

Thanks @rwiegand . We've learned our lesson after the first go. This time we're a darker color like Jacobean. I don't mind a little red coming through if it's a darker stain. Appreciate the input!

Remember that the darker the floor color, the more it will show every speck of dust and pet hair.

I actually like seeing the dirt, so I know I need to pull out the vacuum!

Second in from left, or second in from right, which would be my own preference.

Flooring is not the ONLY element in any design.

There is wall color, there are rugs and furnishings. The obsession of late, with negating every speck of warmth from natural select red oak is insanity.

I redid a home last year, with a natural cherry kitchen. The ridiculous hand wring of a month? We finally said wth, did a clear coat over the old and new flooring.

The house is fabulous now - Plenty of art much of it re framed, super great old and time worn rugs, new paint everywhere and completely kicked in the rear end transitional/traditional.

Don't wring a hand. You've already witnessed the DEATH of "gray floors rage", or am I crazy?

I love dark floors and for the same reason as Chispa I like to know when my floors are dirty . special walnut sometimes works and other times the red still shows I would go really dark if it was my house I would do ebony. If you have to choose from these then the middle one of the 5

I know that water popping opens up the grain of the wood but does it open up the grain so much that it roughens the surface?

Yes, but, it can be smooth out with 220/240 grit. The surface will be smooth to the touch and visually look good. If, you have the oppposite result. The wood may not have been sanded with a high enough grit. Sanding marks will usually be visible.

We have a similar situation and are going to use Bona red out to get the pink out