Pass without trace, chosen creatures must remain within 30′ to benefit from spell?

.@mikemearls /@JeremyECrawford : pass without trace – chosen creatures must remain within 30' to benefit from spell, or only during casting?

— Chris Cunningham (@devnuhl) November 13, 2016

Must remain – range is self, so that tells you creatures must remain in area. #WOTCstaff https://t.co/78kQeqFXLv

— (((Mike Mearls))) (@mikemearls) November 13, 2016

@devnuhl @JeremyECrawfordthanks. Follow-up, does this mean new creatures can be chosen during the duration, if in range? yes, at least from my reading of it

— (((Mike Mearls))) (@mikemearls) November 13, 2016