I've already got the custom accurate hat sorted. It's just the pants colour which is the difficulty now. I'm no expert on mixing colour dyes so would hate to end up with purple pants on the statue, LOL, so will probably have to leave them alone until I can find someone who can make a new pair!
You would definitely be able to dye the trousers with a good result if you apply the correct method. You wouldn't need to mix any dyes if you can find the one, correct colour. I did a dyeing project on some SSC KOTCS trousers and changed them to taupe for Raiders. I learned a lot in the process. Now however, after speaking with others and integrating a 35mm scan I now have into how I perceive the trousers of Raiders, I quite like a light grey/ taupe with touches of pink and purple for Raiders, so very similar to my stock 1/6 Yuan, Y.M.A Studio trousers. For my new 1/6 Crusade Indy, I am using the KOTCS trousers again but keeping them the stock colour.
You could easily dye the JND Crusade trousers if you strip the colour first. The lighter the base/ stock colour, the easier the dye will take to it but stripping first will provide the very best results.
At first I tried dyeing over the sandy/ tan khaki colour of the stock KOTCS trousers. But I didn't use enough dye and or simmer the trousers (to keep the fibres open for the dye to adhere to) for long enough, so there was barely any change. I then over-dyed them. It was a process of trial and error. Eventually, it became a bit of a nightmare and mess, with colours bleeding into each other. So, I decided to strip as much of all of the colour with some hot washes and using Rit Colour Stripper.
To prevent colours bleeding, I think it is best to try to 'one-and-do' the dye, but you should have more leeway to dye a second time if needed if you have stripped the colour first, since colours wouldn't be able to bleed into each other. That said, it might come out patchy/ uneven if you do it more than once. I didn't spend time to try to
totally strip the stock colour as the Rit Colour stripper I used absolutely reeks (I used a pot of boiling vinegar next to pot with stripper and trousers to help take away some of the smell, but it was still very bad). Doing it outside if you can would be the best option.
After stripping a lot of the colour, the dye took much quicker and easier to the trousers. I got them very close to how I wanted and was able to get very close to all of the khaki shades on the trousers in various lightings and settings that I could see on the 4K UHD copy of Raiders. But I did dye once more and then made them a bit too dark and patchy in areas, ha ha! Sod's Law.
One thing I don't like about the hob method is that it does seem to ruin the fibres a bit, since it took out the original, lush sheen of the trousers. Perhaps you could add this back with some product like conditioner, or something else, though. But I know that you need the water temperature hot enough and consistently so for a period of time in order to keep the fibres open for the dye to adhere to.
So, there is a specific science to dyeing, I think. I may try it again with a different pair of trousers.
Some folks opt to paint instead but haven't seen any solid examples of this method.
I hope that helps.