They used common diazo "dumbell" dyes both for resistance to the bleach step and for lightfastness. I'm no dye chemist, but I'd imagine analogous dyes are available from current sources. It was the coating process which was probably tricky in terms of product convenience
and consistency. Even so, each batch was somewhat different and drifted with time and temp. I got good at predicting this and would print
certain images with fresh paper, different images several months later. Inkjet is a totally different concept, and the colorants are very complex.
The nice thing about Ciba is that the three dyes would fade at about the same rate, whereas the complexity of inkjets will mean that some
components will fade much more rapidly than others, and there will be color shifts with time. Ink are composed of either lakes of dyes or
various pigments. There would be no advantage to dispersing them into any kind of film. You'd be much better off using true process pigments like they do in carbon and carbro printing etc. Dye transfer is unrelated to all the above because the dyes are attracted to the
paper by a mordant and must be chosen for this specific kind of affinity.