Can we skip steps in the CI process? (e.g. Compliance Testing)

The Continuous Integration (CI) process is yours to define.  MettleCI ships with a template CI process built from a selection of the available plugins, and accessible using any of the currently available plugin interfaces (e.g. Bamboo or Command Line).  Take what MettleCI provides and edit it, or create your own from scratch. Nothing about MettleCI is prescriptive.  Take what MettleCI provides and use it, or not.  Introduce its capabilities as and when appropriate to your environment, and configure those features to your requirements.