Minimum steps involved for an effective and efficient website redesign process?

I just started working for a web development agency, we work mainly with government so we want to align ourselves within that market with a professional, creative and functional website. We have a great blog and want to highlight our content and whitepapers, plus who we are, our vision and services.

We just started the Discovery phase of the project, and are in the process of doing personas and user journey mapping. I work there in project support and partly as a junior UX designer, alongside the contract designer, who is more of a UI designer than a UX designer, so it's a bit of a learn as we go process. BUT we have a pretty strict deadline of Christmas where we'd like to have the final designs signed off, so we can start developing the site in January.

Our current plan/timeline is:

  • initial planning including pain points and wants for our existing website (done)
  • persona planning (done)
  • user journey mapping and doing value journey canvas for our 4 personas (in process)
  • content analysis
  • IA card sorting, treejacking, review and iteration
  • component mapping and content architecture
  • sketching session of new components
  • wireframing all vanilla pages
  • wireframing custom pages
  • prototyping key user journeys for customer testing
  • customer testing script
  • audience testing
  • prepare customer insights deck to present
  • presentation of customer insights
  • refine prototypes/wireframes
  • UI: Theme and Brand
  • UI Review

Which is quite a lot and definitely won't get done by Christmas this year. So my question, is what is the absolute minimum process required for doing a website redesign?