Looking to darken stain color on 15 year old bathroom cabinets that are in good condition. Rather than stripping, buying new, or refacing, might this combo product be a possibiility?

Similarlly, have new shelving unit, with 3 coats of clear poly, that is lighter than aged pine wall behind it. Any thoughts on how to get a better match (built-in look) or do I just wait?

What is general opinion of a poly-stain product...on new wood?