What is the best way to motivate creative teams (design / developers) in a specific project?

I'm taking my first step in leadership by managing an internal project (I'm working as UX architect and agile project manager). We are will redesigning our company website and some internal tools. The company is small and has shallow hierarchy, although the general culture is not very fast faced. I already built good rapport with dev and design team but they don't report to me. I noticed this trend in previous jobs that I worked as a resource and would like to avoid: 1-if the project is super structured with a lot of pressure ,dates, and specific roles are given, production is faster, but people tend to burn out and creativity, innovation , risk taking diminish, authority starts to get questioned when people feel that tasks are being assigned add no value to improve the product. Projects with this approach have high quality (in terms of quality assurance) but low quality in terms of product. 2-On the opposite side, lack of structure and deadlines also diminish motivation, nothing is finished, people try new things but they tend to procrastinate and walk around the hard parts or just give up. The relationship between managers and production is usually good but the output is mediocre. What is the best way to motivate people in agile development to achieve great success? What I will try to do: 1-Give little structure by assigning roles to a multi disciplinary team, instead of distributing tasks. So for ex. one designer is responsible for both design and vision, so I'm giving him control over his work confined in his space 2-Allow people to fail and have regular meetings to discuss in group what is wrong with the project. 3-Get feedback from users for each sprint (3 weeks), even for low fidelity prototypes, to make sure it's not a one person (me) perspective or just our teams opinions, I got this from HCD methodology. We are doing internal and external qualitative interviews 4-celebrate and reward achievements or any behavior that adds value to the project (outside of the box or what was planned). 5-Do work team work building events (get the folks to a beer night which I already did and people told me that it was a very good practice) Is there anything also that I do or avoid to make me more Successful?