At first glance, it looks like you're doing 1 and 2 correctly. But I'll leave that
up to someone else to point that out.
As for number 3, those settings are incorrect. What it should look like is this:
nss_base_passwd cn=users,cn=accounts,dc=ny,dc=example,dc=com
nss_base_group cn=groups,cn=accounts,dc=ny,dc=example,dc=com
nss_base_hosts cn=computers,cn=accounts,dc=ny,dc=example,dc=com
nss_base_netgroup cn=ng,cn=alt,dc=ny,dc=example,dc=com