When deciding between a software package and custom development/outsourcing, should the analytical step be skipped or reduced?

When it comes to running a company or organization, what are the benefits of using a life cycle model? When adapting a Process Model for a software development project, the following should be taken into consideration:

Discuss the challenges and strategies for managing changing requirements during a software development project, including scope creep and requirement prioritization.

Which process model would you recommend for the incremental development of a software product if the team working on the project consisted of seven to nine individuals, the project had a robust architecture, and the requirements were only partially stable? Describe the occurrence in as much detail as you can.

If you were leading a team of seven to nine individuals in the incremental development of a software product for a large project with a solid architecture and only loosely defined requirements, which process model would you recommend? Describe the situation in great depth.