You are right. I think all of them are good for 3-4 years except developer C (could be one of the other ones) it's only good for 1-2 years. It's colour goes off and it's not good then. It's life can be extended by keeping air out and storing it in the fridge (not freezer).

One question I have about colour development compared to b&w is, do you people tap the tank to dislodge air bubbles? I do it all the time in b&w, but I've not seen it mentioned in instructions or for that matter anyone doing it in the videos I have watched.