You've got a solid checklist already, but a couple of additions could enhance your process. In the intelligence gathering phase, considering social engineering aspects might be useful, as they can often reveal vulnerabilities that tools can't. Also, during post-exploitation, think about the potential for lateral movement or pivoting to other systems, which can provide a more comprehensive view of network security.
For different environments, tools like ZAP or Burp Suite might be particularly useful for web and cloud-based assessments, while for on-premises, you might focus more on traditional network tools and domain-specific exploits. Customizing your approach based on the client's tech stack and industry-specific threats can also provide more tailored results. Keep experimenting and updating your process as you gain more experience!