all chicks from cuckoo maran will hatch out black with white on back of head, white on wing tips etc. the only exception would be half of the chicks out of the red sex link and ca white will hatch out cream with random black spots. so that rules out cuckoo maran x buff brahma(yes,chicks from this will all be black with white on head).
if you got the ca white as day old and it had black spots that is a very typical look for dominant white crossed with a colored chicken. if you are seeing this with the chick it absolutely points to either the ca white or red sex link as they are the only ones with dominant white in your list.
are there other young/adult birds not listed?