Wow,you put a lot of sweat into striping. There is no silver bullet for what you are asking. It takes years of trial and error to develope ability to make 3 different species of wood look good togeather. That bears repeating "LOOK GOOD TOGEATHER". Too often people attempt to match when it's just not possible. There are 3 ways to approch it,#1 hire a pro #2 aquire a color wheel and study the art of working with color until you unddrstand useing the wheel. #3 Choose a system from those offered within a brand and stay with it from start to finish. Min-Wax is destained by pros but I feel it has it's place amoung novice wood finishers so that's the one i will talk about as illustratin only. Within one of thier systems there is a wood conditioner that prevents uneven stain penitration on among other wood,pine. It works if directions on can are followed but many fail because they wait too long between conditioner and stain. That means you can not condition all the pine shown before starting to stain unless 3 or 4 people work on it. Do a section of conditioner then stain it before doing another section. Needless to say, quility of result deminishes as you go from option #1 to #2 to #3 but a dedicated #2 can often do a better job than many #1s.

The wood looks more like Fir than Pine. Fir will actually take a stain evenly without blotching. The wood visible in the triangular section of the upper right corner does look like pine. Like mentioned above, it is going to take some trial and error to make different woods match.

The putty is not going to take a stain. I would carefully dig it out and experiment with some different products and colors.

aidan wrote, "The putty is not going to take a stain. I would carefully dig it out and experiment with some different products and colors. "

Agreed,and you should use putty from the same "system"so it can be tinted if nessarry.

A clue to wood species is if it's yellow pine you will smell turpentine while sanding.

Forgive me for adding to the mix but as I look at the pictures in this and your other post I visulize leaving the wood as is and clear coating or tinting only enough to blend and clear coating. The posts could be painted white,black or subdued pastel replicateing milk paint. Ofcourse I'm only emagining the 125 y.o. house looks like the stairs which shout "farm house".
That's my 40% of one nickle.

You could just dig out the filler, and leave the gaps, as it is a 125 year old house it would add to the character. If you really wanted to you could have someone make replacement pieces that would fit better.

Hi,
As a restoration carpenter/cabinetmaker, I would take it apart and reinstall to close up those gaps, probably adding wood at the base to fill in what's missing/settled, perhaps a wider shoe molding.
To me this is a mystery to be solved and remedied via woodworking, not fillers or "living with it"; it was not that way when it was new.
Casey

I'm with sombreuil_mongre. reinstall, that looks like an awful lot of filler. I also agree it looks more like fir than pine.