Since both breeds are basically mixed breeds that lay colored eggs it may be impossible to tell. Looks like an Easter egger to me, and the description of the prairie blue bell egger sounds like another version of an Easter egger to me. I suppose if you get a blue egg it could be the blue bell.
Easter egger is more of a type than a breed. If its a mix breed bird, no matter its heritage, bred to lay colored eggs, its an easter egger. And bluebells are mixes; the same way a labradoodle is a mix.