'Pearly' usually means like a pearl, which is not a colour thing but a reflective effect. Pearlescent paints are available if you want to go that route and adding a little metallic paint (or metallic medium) to normal colours can work okay too. Liquitex interference colours are well worth trying for this kind of thing, although in common with most metallic and iridescent paints the sparkles tend to look a little overscale on minis.
If you go with pinkish colouring I'd strongly recommend lining up photographic references to get the colour right for the darker mixes - the colours are very subtle, more a faint salmon than pink per se.
I'd probably prime white for this. Grey could work fine but I'd probably undercoat the areas in plain white before working on them in the pearlescent paint, although thinking about it layering on a transparentish iridescent paint directly over grey primer could be a good starting point for the effect.
Einion