I would let this one go. In the pictures, at least, the difference is subtle and doesn't bother me at all. It looks like the flooring was factory-finished, the stairs finished on site. If the processes and materials are not identical, so you shouldn't expect their appearance to be identical. Your contractor might manage to satisfy part of your preference, i.e. make the stairway less reddish, but cause some other problem in the process such as making the stairs noticeably darker. The risks and costs of futzing with this are real, and the potential benefits seem small. Unless the photos are misleading, I'd focus my energies elsewhere.

I don't know how they do it, but it might be interesting to have the island lighter with the color of the cabinets painted over it, and than wiped off, to just see the dark highlights in streaks? BUT, if having the island darker is your preference as someone said, due to other wood in your home, than when you see the whole picture, and the appliances in play, you will see a different hue in all your surfaces. I don't encourage WHITE OR DARK in a kitchen. DARK is hard to keep the smears and dust off to look CLEAN. WHITE, is going to yellow with time and especially around the cooking appliance where fumes and grease go airborne. So your cabinets are the pERFECT color of a creamy yellow, not a naseous LEMON or an ORANGEy yellow. Light in a kitchen as yours will be very nice and the colors of the walls such as just the right warm taupe color or pale gray, or just the right dusty blue, or even dusty green-gray or gray-green, show you have versatile basics that will stand the test of time as soft good colors come and go, for window treatments and linens. I read somewhere that in paints, the most timeless choices that wear on one to 'live with' long term, lie in the 'dusty' shades family. I think there is some truth to that. Being there in person, you will be able to make the best judge, and you can always ask someone you trust to confirm your decision or guide you to an option you have not thought of, based on all the ideas you have seen here. It's great to have so many options!

This is the downside to vinyl, the company eventually stops making it. If you can't find the exact match go for something completely different, however since its only in the living room it might be worth replace it so that there is cohesion between upstairs and downstairs. Also, yes this that unsafe staircase needs to be addressed.

@dahkee1 our current house has very large windows except one over the sink in the kitchen which was made smaller purposefully. People do that-- put in a small window over the sink or in the kitchen to line up with cabinet heights. Your windows look like they are winking! If it bothers you, I would get some a nice planter box and add some greenery/flowers under it. That will give it visual weight and help line it up with the base of the other window. I actually kind of like this little winky window. Your landscaping is lovely-- just trim it up a little and add a cute planter. Done and done.