The HR Manager was able to utilize the specific skills of each member of the team assembled for the project.

Utilize means to make practical and effective use of something. Harness, in this context, means to control and make use of natural resources, especially to produce energy, or to use something to achieve a particular purpose. Harbor means to give shelter to; harangue means to lecture at length in an aggressive manner; herald means to announce. Therefore, harness is the correct synonym for utilize.