If the cracks dont go past the edge of the sticker then it should just be the sticker that has cracked.
Fins - the C3 Venom fin are great fins, and are very quick off the wind and very forgiving. These are my favourite fins, and you can use these fins as free ride fins or speed fins. If you want better upwind perfromance then you might want a stiffer more upright slalom fin. I cant comment of the other fins as I are'nt familiar with these.