Hey Elvis,

Yep, like you discovered, those toners won't do the trick. You need to actually replace the silver with dye somehow, so that the dye is in proportion to the silver. Highlights should be clear (just as they would be with silver) and shadows full of dye.

You're also right about needing 2 separate light sources if you're going to use filters to create the color; this is heading into additive country. You could do this too, and just use silver negatives with appropriate filters to view each through. The trick here is that you'll need to combine them for viewing somehow. This is analogous to the Kromskop.

You could try dye mordanting with basic dyes (something like this, pg. 755), or making a gelatin relief image and using acid dyes, like dye-imbibition.

Basic dyes have no affinity for gelatin, hence they need a mordant which can be made via the silver, whereas acid dyes generally are attracted to gelatin and so all you need is a gelatin relief image (think carbon method, or you could try a dichromate bleach). Realistically I think those are the two best paths.