I download a stock G900F rom , cook it with ArchiKitchen with ANCE modem.bin (need to specify boot and modem block). Modify others.xml for displaying NFC icon, disable shutter sound, and enable recording. Also modify customer.xml to make AT&T's default APNs (except FOTA and security strings) so data works right after the first boot. Disable Knox with Archi and no more annoying notification.
Totally stock.
Didn't check root yet but I believe it might have gone? I did not root my rom so I suspect it might have gone?
EDIT: Check with Root Checker and the it doesn't appear to be rooted.
were you able to root again?