@James Thomas A few things to add to your search criteria:
1. Bigger Pockets Agent Finder is a good resource, but don't use it exclusively. I think its important to know that Agent Finder is a paid service, so the agents that are recommended to you are the agents that have chosen to pay Bigger Pockets thousands of dollars to be recommended, not necessarily the best agents or the agents with the most experience. Often times its the opposite- the best agents work by referral and keep busy without paying for marketing, so they don't pay for Zillow, Bigger Pockets, or other service's "featured agents" advertisements.
2.Look for investor-agents that have personal experience in your Niche. If you want to HouseHack, don't chose an agent that hasn't HouseHacked at least once, ideally multiple times successfully. Ask detailed questions here about experiences, dates of investment, and addresses / example addresses. As the popularity of HouseHacking and Investing has increased I've seen many agents suggest they have HouseHacking and Investing experience as a way to win clients, but that experience may be very limited or even not existent... make sure to ask probing questions to get the full story!
3. Recommendations & Reviews: Make sure to read lots of reviews and ask for referrals / recommendations - that's what's going to give you the most information about what working with this agent will actually look like!
Looking forward to talking more. Cheers!