a further thought for things to take specifically for the Revillagigedos (Socorro) are the biggest fins you have/are comfortable with. I took tech fins, but there's no need for nuanced control on any of these dives, and a few times I wished I'd taken longer, more powerful fins for dealing with current. Our two dive guides both had long, carbon-fiber free diving fins which seemed perfect for these dives.
I took a reef hook, which was useful, but there was always a rock to hold onto and no-one else seemed to suffer unduly without a hook