What should we consider?
Ash
White Oak

Walnut is great but we already using it for island top and it is very expensive around here.

Patricia Colwell Consulting, pretty much nailed the answer. White Oak is ideal for an onsite custom stain and its about 30% harder than Black Walnut while being less expensive.

Hickory can be a little tough to stain...once it takes the stain the movement is greatly reduced. Not completely gone but greatly reduced. It has to be stained a deeper "mid tone" because it can get blotchy if you try to work it "too light" with the stain. The darker the stain the more uniform the colour. Takes a very good stain master to get it stained. The professional you hire has to have worked stain on hickory before.

And remember: hickory is not as stable as white oak. Especially in a wide plank. The wider the plank, the more unstable it becomes (more shrinkage/expansion between the seasons). This is true with "hard" hardwoods. Certain cuts are more stable than others, but a wide plank hickory is going to move more than white oak.

If you want a mid-tone stain and a wide plank, you may want to look at white oak. It ticks all the boxes. When it comes to "yellow" and "red/orange" tones, some of that is the finish itself (not necessarily the stain). An oil based polyurethane = orange/gold when dry. If you want to stay away from those colours, you will want to stay away from oil based or oil modified finishes.

That means a "clear coat" (aka water based finish) is what you want to look at. That means your flooring professional has to be TRAINED on water based finishes...and water based stains. Oh boy. This is where things go side ways.

You would think a wood finish is a wood finish...but they aren't. Each material needs plenty of training. Someone who has never worked water based finishes will fail HORRIBLY the first 5-6 times they work with water based finishes. Without a training course (or 3) under their belt, they will have a very, very tough time working the water based stains and the water based finishes.

Hardwax/oil finishes, such as Rubio Monocoat, also have heavy training requirements because of the "different" techniques required to get it down. Once the technique has been LEARNED, it is nice stuff to work with...but the finisher still has to LEARN the technique before they move on to a full floor finish.

As you can see, the choice of hardwood is the easiest part of this question. The choice of finish and the choice of hardwood PROFESSIONAL is the REALLY hard part. If you have concerns, please work with an NWFA Certified Sand/Refinisher. You can find a list of names on the website: www.nwfa.org

Have fun.

Great advice. Thank you.

To clarify, we are looking at 6-7" width boards. I assume that qualifies as a wide plank flooring.

We have the option of buying the wood finished or unfinished .Have time to take a trip to the finishing company and see if they pass the sniff test with water based finishes.

Is it still true that you get a more durable finish when factory applied (controlled environment)?

The downside of "factory" finishes is that for scratches/wear the only avenue is completely refinishing the floor. With specialty finishes of the hard wax variety they can be reapplied to damaged spots after a bit of careful prep to sand out the damage. So it depends on what suits you - if it's a forever home go with Pro applied Rubio or similar. And as an aside hard wax doesn't have that artificial plasticky shine that some people are getting away from now. So if you prefer a more green product that gives you a true natural wood finish that would be my choice.