Okay, so I made some mistakes (and hopefully I can keep someone else from making the same mistakes):
The reason I couldn’t get the task to start was because I had “Max Clients” set to 0 under the storage node. I had thought that 0 was unlimited, but it looks like 0 literally means 0. My mistake.
After fixing #1, the task would start but the image client would boot and then immediately fail to start the task. I removed the fog directory on the storage node (/opt/fog), removed the node and group from the fog management screen, then re-installed fog with fogstorage for the mysql user and the password shown under “Other Information >> Fog Settings >> Fog Storage Nodes” in the management interface. The first time I had set up fog on the storage node, I had created a new mysql user on the management node with a different password, which I now realize was wrong. My mistake again.
After fixing those two mistakes and following the guide listed by Jaymes, I’m now able to successfully image remote clients. It’s been so long since I’ve set up Fog, I’ve forgotten how to do everything, but I’m glad to see this community is still active!