All of the concepts need to be more green and more treed. Avoid creating a heat trap.
Grass and heavily used gathering spaces may not go well together, but trees would provide an excellent shade canopy. The result would be a very welcome oasis especially during the increasingly hot summers. Using water features as part of a storm water management strategy will be both functional and an excellent civic feature. This could be a public space that also tells a strong sustainability story for community benefit. Offering wifi connectivity throughout the space could also be a benefit. Also a variety of seating ledges that can be used to rest and relax on normal days, and convert to audience seating during festivals. Avoid an all hard-surface plaza if at all possible... make this space an attractive alternative to the hard scape streets and sidewalks of the downtown area.
Jane Underwood commented
agree with above comments