Following, I have some hatched in March and April (different lines) that have quite a bit of darker spots in body feathers and am watching for changes as they mature.
I believe your wheatens/blue wheatens are bantams and Andrew's are large fowl. Even though they are the same variety there may be some minor differences in the genes that produce them. His "#1" photos of the pullet with random black spots is similar to LF birds Royce, Duane, Beth and I have produced and discussed, as Royce mentioned. Calico and mosaic were some terms we used before to describe it. Although it could happen, I don't recall anyone saying they've seen this in bantam wheatens.
Birds are judged against the Standard when mature and I know day-old chick phenotype can indicate a lot about mature colors/pattern, but these in-between awkward aged started birds sometimes just need time to mature before judging those areas. Combs and some other comparative traits can be judged against siblings of the same age.