Hey, welcome to the forum Tron!
Was this ordered thru showcase or did you asked for a custom body???
I may say you that the 1/8" thick Spalted Maple won't change the sound of the guitar in no way... Even if it was 1/4" thick, the change would be small...
The strat is routed for humbuckers or single-coils?
The fretboard and neck depends on what kind of tone you're looking for... Also Warmoth does not put Spalted Maple veneers on straight headstock, because it has to be bent to fit and bend Spalted is a little worky with some chance of damage on the veneer... Some luthier could do it for you, as it has a more "one at time" approach (Warmoth is a company that build awesome guitar bodies and necks, but they're orient as a line production)...
Anyway, I suggest a neck wood that doesn't need finish, it feels amazing!
Are you looking for a very traditional strat sound?