Gus,
Firstly Congratulations on having a most excellent interior color scheme!
In no particular order:
Carpet - I bought a dark blue 2-piece carpet from ACC, have not yet fitted it but the quality of the pile is excellent and the color nice and dark.
Door Panels - mine are by PUI and are a few years old now, but the color when I got them was very close to my original passenger side door panel, which was protected from the sun since the mid-70's. I have heard owners say that the latest concours door panels by TMI are good in terms of the vinyl appearance (grain, padding and seaming details) but I have no direct experience of these. Legendary Interiors also seem to be offered by all of the usual vendors, but I haven't seen much in the way of opinions or reviews by owners......
Seat Covers - I can't recall with certainty which brand of seat cover are on my bucket seats, but I *think* they are PUI. Happy with the grain, fit and quality. Again, these are also offered by Legendary, TMI and Distinctive, can't really offer advice on which is considered the best at the moment.
I need to replace my dark blue headliner, haven't looked into that yet, but from your sig, it looks like your car is a 'vert and so no headliner required!
Unless you're aiming for a trailer queen concours car, I'd suggest that any of those well-known brands' products would be worth considering. Most offer a range of quality, from budget to 'best', which is self-explanatory. I think the most important consideration is to get the best quality you can afford, and all the door/rear panels from the same manufacturer, and likewise for the front and rear seats; that way, they should match.
The hardest thing to try and get right is if you have to use interior paint on the metal areas of the dash, and on plastic components like kick panels and console (if you have one).