LyndaOH, I would say yes to both, maybe firstly to avoid teaching the Y seams in a mystery format, and then to keep things a mystery. Bonnie goes to great pains to do the latter, I think.
Belfry, I think those must be from another project.
Since this star block is so easy to put up without sewing, I decided to do that. That will give me a good perspective in choosing what direction to go with my neutrals. My thoughts are that were I doing this with foresight, I would choose lighter reds and darker Scandas (med. blue). I have about three blocks with optimal contrast, and I think the others all have value issues because of either lack of value contrast within the pinwheel (thanks to the darker reds, but I did want to use stash), or the lack of contrast between my aquas and Scandas (I had trouble finding this shade and settled for some very light ones). But I guess that's part of the fun of a mystery -- working blind and seeing what you end up with!