to customize all editions you need to first mount the first edition -> remove/customize it -> save to wim -> start again winreducer and mount edition 2
an so on, so you need to customize each edition seperatly
but dont use this option:
ISO - Boot - Delete Unneeded Editions ISO - Windows - Delete Unneeded Editions
if you use this 2 option all edition will be removed exept the one you mounted