Previously, the instructions for the final project stated that a project in REDCap needed "longitudinal data collection" enabled. That's not quite correct.
It's still true that, as stated, REDCap final projects must "use at least one repeatable event or repeatable instrument as in Labs 2 and 3." But the simplest way to do this is to use a repeatable instrument and leave the "longitudinal data collection" feature disabled.
We're correcting the instructions right now. I'll also post something in the discussion group about the difference between repeatable instruments and repeatable events in REDCap. TL;DR - repeatable instruments are simpler.