As gjm mentioned, don't bother thinking through straight forward problems that already have plenty of empirical data on them. Just look up the data. Two minutes on google brought me to this study:

In-class activities led to higher overall scores than any other teaching method while lecture methods led to the lowest overall scores of any of the teaching methods.

That's just one example. I'm not going to bother with a comprehensive review of existing research. I've heard it from a wide enough variety of sources I consider reliable that project-based learning is extremely effective that I've always considered it a low probability that careful research on the issue would reveal anything especially useful. Also, your proposed problem of learning in the right order has absolutely no relationship with project-based learning. If you need to learn A before learning B, then choose a project that focuses on A before picking a B-based project. Both active and passive learning can lead to A, B, C, and D being taught out of order, and both can be used to teach A, B, C, and D in order as well.