Buildroot/busybox usertable.txt and take away access rights for a group/user

Question

Question 1: Thru buildroot usertable.txt I created a user called deviceuser which belongs to group operator and nogroup:

$cat usertable.txt

deviceuser -1 deviceuser -1 =SERIAL_NO /mnt /bin/sh operator Device user for non-trivial maintanence work

After image is loaded into target what I get in /etc/group is :

root:x:0:
daemon:x:1:
bin:x:2:
sys:x:3:
adm:x:4:
tty:x:5:
disk:x:6:
lp:x:7:
mail:x:8:
kmem:x:9:
wheel:x:10:root
cdrom:x:11:
dialout:x:18:
floppy:x:19:
video:x:28:
audio:x:29:
tape:x:32:
www-data:x:33:
utmp:x:43:
plugdev:x:46:
staff:x:50:
lock:x:54:
netdev:x:82:
users:x:100:
admin:x:1002:deviceuser    <====== not sure where its coming from 
nogroup:x:65534:deviceuser
deviceuser:x:1000:
sshd:x:1001:
operator:x:37:deviceuser

$ cat /etc/shadow

root:$1$blahblahblah.:10933:0:99999:7:::
daemon:*:10933:0:99999:7:::
bin:*:10933:0:99999:7:::
sys:*:10933:0:99999:7:::
sync:*:10933:0:99999:7:::
mail:*:10933:0:99999:7:::
www-data:*:10933:0:99999:7:::
operator:*:10933:0:99999:7:::
nobody:*:10933:0:99999:7:::
deviceuser:$1$blahblahblah:::::::
sshd:*:::::::

As noted above, deviceuser gets admin priviledge and I need to eliminate that and make deviceuser part of operator and nogroup only.

Question 2:

I want to take the access rights (read/right/execute) away from this deviceuser or operator group for /etc/ folder, while keeping everybody else's permissions intact, there are a number of users and groups in the system including www-data. What's the simplest way to do this without affecting any kind of permission issue for www-data and others?

If I do "chmod -R o-wrx /etc " then I believe www-data will have issues running some init scripts.

Thanks Ratin