I would be careful with the ;-seperated ones, as that could mean both white and red. For the others I would say white-red as in the marking for a GR footpath.
Where I live we are currently mapping a walking network. It consists of coloured routes and choice points. We map the whole routes as a roundtrips as well as the single segments between choice points (as you should in a network). For those segments it gets the colour value for all routes that follow that segment (and all colours are signed in between choice points). Using a single colour or not tagging colour at all does not seem correct to me.
