ILM ignores the setup.template.name and setup.template.pattern options. You need to use the defaults to have the built-in policy work. (source: https://www.elastic.co/guide/en/beats/auditbeat/current/ilm.html)
Setting up your own ILM policy is possible. You'll need to manage the template yourself and follow the steps in the ILM tutorial. But consider using the default index naming so you can use the automatic ILM setup. The indices include the version for a reason. It make upgrades easier and prevents conflicts in mappings/templates.