Iterative and interactive.
A cyclic approach does not necessarily mean a vicious circle. Why not try an iterative approach and build a virtuous circle?
Rather than going full speed in the tunnel and seeing nothing else than the expected light at the end of it, an iterative approach gives room for a core bundle of priorities. You start building on them while in parallel other workshops can start.
To avoid the tunnel effect always ensure the project steps are not in a fixed sequence, rather make sure iterations are allowed, like cyclic patterns becoming concentric on tough details but also in expansion to broaden the scope and ensure integration with other modules.
Not knowing how the full picture will exactly look like does not prevent you from building several dimensions! Then, navigating among the on-going topics in an iterative way, you add the layers that build a strong and integrated structure.
This approach depends entirely on a well integrated network of people interacting with each other.
As much as process steps are connected to form an integrated end-to-end flow, it takes only a second to realise that communication is what links people together.
Interaction is key!