I would think about adding more clutter when you do release the littles. It won't look as nice as it does now, but once everyone is getting along you can tidy it up.
This is what my big coop looks like at the moment as we introduced two new groups of chicks to the pullets that were already out there. The oldest pullets are 17 weeks, then there are two 7 week old cockerels, and 32 5 week old chicks. So far everyone is mingling nicely