The white on the back of his head isn't as large and distinctive as a lot of pied splits. But if it's always there (as opposed to being caused by a molted feather or messed up 'hair') then I'd say he's split pied.
Personally I don't have confidence in the signs of a whiteface split. Except for the ones who are visual whiteface, ALL my birds have the signs. I do know that 4 of them are definitely split, but it seems a little improbable that all of them are. My pearl hen Ladybug has a whiteface mate (Pip) but so far they've had zero whiteface babies. I'm not quite ready yet to declare that she's NOT split whiteface, but if there aren't any WF babies in the next clutch then I'm going to assume that she's not split.
Ghost pearls occur with both visuals and splits, and apparently they appear with the infamous 'spot gene' too. srtiels says that a visual pearl male will always retain some mottling on the upper part of his tailfeathers so you can check for that. You can view her collage at
http://s525.photobucket.com/user/Mouseb ... rt=6&o=113 and check out Frankie's tailfeathers.
But also check out the thread at
https://www.facebook.com/groups/ICR.uni ... 797401791/ because it seems to me that tailfeathers can be hard to interpret. Pip has grizzled/mottled tailfeathers which is apparently a pied characteristic - he hasn't had any pearl babies. Azazel also has bleached-out looking areas on his tail which change over time, and I don't know what they mean because he hasn't fathered any chicks that I know of.
Edit: wait a second! He has to be split since there was a non-pearl baby. Two visual pearl parents will have all pearl babies. Unless you think there's a chance that the hen mated with both cocks and the grey baby is Yoghi's.