Systematic review teams consist of three people at a minimum (2 screeners, 1 librarian) but can be much larger.
Project lead - This person may assist in multiple parts of the systematic review, but they are responsible for seeing the project from initiation to completion including project schedule is followed, managing and submitting the manuscript for submission.
Screeners - Systematic reviews involve two stages of screening, title/abstract and full-text. it is recommended at both stages of the screening process, screening is completed by two individuals that should not complete the screening together.
Search specialist - Working with a librarian or information specialist to develop your search is recommend by the major systematic review handbooks.
Statistician - Depending on the nature of your systematic review, particularly if you plan to conduct a meta-analysis, you may require significant statistical expertise.