What fabric are they? If it could be done, it would probably depend on where you live (in a large city) and whether anyone in the area would do it (like a custom dry cleaner). But the cost might be more than new draperies. And if they are lined, depending on the combined fabrics, if they can be wet, one side or the other might shrink and ruin them.

I think the short answer is no. Without seeing them and knowing the fabric one cannot answer, but I think the dye process would ruin them.

No. They would most likely not even be washable. Custom is usually dry clean only.

Probably not.

The only way to find out is to take them to a trades place that is willing to do the work and find out what it costs. I would imagine that any place would not do it unless you signed a waiver against it not turning out as expected AND your paying for it in advance.

As others have posted, any kind of expensive window treatment is going to be expensive to dye - if you can even locate anyone willing to do it. And it's likely that after having spent the money you wouldn't be happy with the end result anyway.

I also find the fabric itself could have been more exposed to light in one part more than another and create a dye job that is not uniform . Post a pic and see what pops up for help.I had a set of drapes made in a sheer colored fabric to hang over a set of white drapes that worked to bring a color into a space it was a really nice look too