Balancing more than one student in an authentic project can be a little tricky. With authentic learning you want each child to be able to explore and follow leads that interest them. So, what do you do if you introduce a topic and then your students go off in different directions.
Even if you are working with a small group, it can be a challenge to follow each student on their journey. You also don’t want to lose control of the project.
The important thing is to keep in mind what your objective is. If you introduced a project about the ukulele, and one of your goals was for your students to create a time line about the history of the ukulele, you need to decide what you really want your students to learn. If the concept of developing a time line is the objective, then that is what you focus on. So, if one student stays with the ukulele, one goes with a flute, the third get interested in marching bands, and the fourth moves from marching bands to football, they all can create a time line about the history of their interest. Even in a large class, everyone can be working on time lines.
If it is important that all students learn about the ukulele, this can also branch out into the history of the ukulele (history buffs), writing music for the ukulele (musical talents), building a ukulele (construction fans)…
Just keep in mind what you actually want/need to accomplish as a teacher, and then let your students fulfill your goals following their passions.