This is the beginning of a great list, but to apply everything without careful understanding / adapting to your situation would just end up confusing people and causing them problems. Some things are also very distro/environment specific (like the mounts layout).

There are tools which will verify the situation for you, but not force a specific solution.

There's https://github.com/openstack/ansible-hardening and https://github.com/dev-sec/ansible-os-hardening

There are already some automation packages around, in dev-sec project we have them for ansible/puppet/chef including automated compliance tests for inspec.

https://dev-sec.io https://github.com/dev-sec/

(disclosure: I'm core maintainer of dev-sec)

Instead of one role for hardening, I try to write my roles with secure defaults: https://github.com/liv-io/ansible-roles-centos