There are melanizers that can increase the amount of splashing. The splashes are where the melanin managed to break through despite the dilution.
Splashes that come from more strongly patterned blues are likely to be more strongly splashed.
Genes can compound and if darker birds are bred they...
Mottling is caused by the mottling mutation, which is recssive. Exchequer is simply a different mottling allele.
Ermine Ameraucanas are just paint.
Silver spangled is polygenic and more complicated. It can be either birchen or partridge based. The genes causing the pattern are ginger, melanized...