Yes, it's a good idea and we're aware that we need this information online. However, a thread with many posts in a forum is probably not the best format for this information. I did a Bimac Care Sheet, and one possibility is to have care sheets for all common species.
Another idea for compact information is a "sticky", an infrmation post at the top of a forum, as you suggest.
In the meantime, you might read the sections in the book Colin and I wrote, Cephalopods: Octopuses and Cuttlefish for the Home Aquarium. You would find information on bimacs, aculeatus, briarus, mercs, and some others there. Vulgaris is really too large for most people to keep, but that's also discussed under Large Octopuses.
Nancy