The coding standard makes it easie rto do collective code ownership, giving the project flexibility in who can take on which tasks. It helps reduce unnecessary specialization. Testing is about feedback - knowing what works and when. It is about confidence - the confidence that you're making progress. It's about communication - learning what's needed, learning how to understand the customer and how to communicate needs.
Testing is key.
Don't do less, do more. Refactoring is the process of improving the design of the system every day. The only possible substitute for refactoring is to do more design up front, which will reduce feedback through focus on what you imagine the design should be instead of on what it really needs to be. Frankly, I don't see how you can survive without it. Forty-hour week means that the team doesn't work until they are near death, just until they are tired.