Hiya sounds fun !
How about Salt dough starfish, or playdough ?
Easy addons for texture could include sand, buttons, glitter ..
The cultural aspect could be how some people keep marine tanks with Star and other fish in .. do the Children have fish at home that they care for or maybe know of someone that has ?
Types of aquarium or tank setups that you could talk about, cold water, warm tropical, outdoor ponds - rock pools and swimming pools ..
could look at conservation work/pools as well + places that sell, breed and display fish.
There is huge potential for relaxed math in this activity as well, shape, counting, colour, symmetry.
If you've time you could 'promote culture by having a few Rocks sat on sand somewhere so that the children can put their Starfish onto them once finished.
Image search for Starfish
Wikipedia Star fish article
We've just had to be very very firm here and separate our boy & all our girl Guppies ... and the zillion teeny weeny babies
lol .. fish on the mind !!
Hth xx