Yes, I believe just like other Google documents they can be edited by multiple people at the same time. However, you'll still need identical file structures within your respective Google Drives (e.g. all your data living in identically titled folders with the same relative paths to your Colab notebook).
I'm not entirely sure why you would want multiple people editing at the same exact time, though. This could cause global variables to be reset or changed without your knowledge. Additionally, just like a Jupyter Notebook, cells within a .ipynb file can only be run one at a time. Meaning one person would always be waiting to run code.
My suggestion is to create seperate exploratory Colab notebooks for each team member.