I would add that I think the other level of expertise they need is in how to conduct a workplace investigation. This is not a regulated industry. There's no college you can go to, to get a certificate or a degree.
The danger, of course, is that they really botch a process and do an enormous disservice to the people who come forward. On this front, lawyers for sure have an advantage because we learn in our education and through our practice various aspects of due process and natural justice, things that lay people don't typically learn. It's not a practice that needs to be exclusive to lawyers, but those who are not legally trained certainly need to obtain that equivalent training somewhere.