I’ve been observing these caterpillars in the garden for the past 2+ weeks. Is the difference in color due to the fact that it is two different species, or simply because they are in different stages of development?

(I have noticed skin shedding.)
Butterflies spotted and identified: Garden Acraea & Dancing Acraea
Uncertain, but possible as I have observed more than two Acraea species: Blood-red Acraea & Natal Acraea?