Not sure about the quality of code you’ve got from your freelance developer?
But it’s better not calling them peer reviews because it puts too much focus on the peer, that is being reviewed, and not enough focus on the code.
This table could also provide you guidance while selecting an appropriate review technique.
Aside from that, there are two human problems that code review also solves:
Team Synchronization – it allows you to be certain that all team members have a good concept of where the architecture is going.
If your team does not have this vision, you’ll eventually spend additional resources on add-ons, redevelopment, and recompilation.