The predictions are virtually useless to disentangle such effects. I teach that all different constraint sets are equivalent because they give the same predictions so choose that set which is most appropriate or most easily interpretable for the problem at hand. In other cases, special contrasts need to be set up. Contrasts are a property of a variable, not a design so that it would be nice to have an automatic way of doing this for each factor variable rather than a global contrast option. But I know of no software that allows this.
R makes it extremely difficult to understand codings.
They are very obscure and easily lead to errors of interpretation. That is my whole point. As in I stated above, in a part that you cut, to pay attention to the contrasts options that I set. Single levels are at least as relevant here as for any other contrast set. The coefficient for WM is minus the sum of the other three.