First picture is finisher error. His sander messed that up. How does it look standing up approximately 5 ft away, as that is the acid test in determining acceptability for the finish. Also if that is the only spot the cure may make it look worse.

Pics 2 and 3 appear to me to be just the base wood and the way it took the stain.

Thank you both so much! This has been a big help.

#1 = poor finishing (fine sanding & edging) those swirls are "edger" marks, and should have been corrected long before the stain was applied. There's also "screen marks" which are finer than the more obvious swirls.

#2 = looks like more of the same, although reverse... sanded/burnished more than the field area, which makes the wood less receptive to accepting stain.

#3 = just some "wavy grain" similar to burl... you'll find that in almost all natural wood products.

Thank you!! Your explanation on #2 makes sense on another issue as well. The area that didn’t take the stain very well is sanded more than the rest. They needed to sand the new floor on a plane to meet the old. New planks were about 1/8 inch thicker. This was another thing I was unsure of; the sanded plane along each perimeter is pretty drastic resulting in a slightly seam-puckered look. My husband only noticed it when I pointed it out. I am a perfectionist so this bothers me, but I don’t want to be expecting too much. Is this acceptable or should it have been sanded more gradually?

Agree with above but want to add that wood floor refinishing will NEVER be perfect since it's done by humans. If something is 95% perfect, or very close, leave it be. The last picture indicates that your floor generally looks quite nice. Unless it has a fatal flaw in a conspicuous area, leave it alone. Redoing it could easily end up having more issues than you have now. And face it, as soon as your floor gets walked on and used, it will no longer be as good as it was when new.