Actually I think peacock is a pretty popular theme right now for weddings and if done correctly I think the iridescent on iridescent can look really nice.
In answer to the question about what colors go with the peacock blue -- look closer at the peacock and see the different colors that are already there, yellow, green, deeper and lighter blues.
Hi Ty, great colour theme, here are some jewelery ideas for you and or the bridal party, remenber as well as the yellow works with the blue so will gold.