It'll be interesting to see if the toners can do the trick; maybe so! There were a couple dye-toning tri-color processes too, so it just goes to show you that toners can create a wide range of usable colors.

I've not really looked at the mordant processes seriously yet (in terms of the procedure) so I can't be certain when in a reversal process you'd wanna stick it. I think though, that you'd need to develop up the positive silver before you could turn it into the potassium iodide mordant, viz. the Ives process.

Finding dyes for this might not be hard. There are a thousand basic dyes on eBay that are used in biological staining and other things. Malachite green is one from the top of my noggin.

Alternatively, if you look at Capstaff's patents on this process, his method for sticking the dye in the gelatin is by a dichromate bleach not unlike one found in reversal processing or carbro. Heck, the first patent (IIRC) goes from a negative to a dyed positive via this bleach in one step. He later patented a method to do this from a positive to a positive (better for printing to movies).

Although chrome salts can be mordants, in this instance it's not strictly lending any mordant action, but rather it's the hardening differential set-up in gelatin that "involves" the dye. This requires acid dyes, loosely speaking, that might easily be found in the textile industry.

Sorry if I'm repeating myself a bit; some tricky concepts here, and I don't think it hurts to reiterate and say things differently. It certainly helps me make sense of it all too...

In the end, I hope you give it a go with any method you like!