Superman Cinema (the link you provided) will explain each of the different versions of the film in exhaustive detail. Use the links in the left-hand menu to access the notes on each film to explore all the individual scenes and which versions they show up in. It's a site well-worth bookmarking.

These scenes were never seen in wide theatrical release, though there have been limited showings of the 2001 Expanded Edition (the official title of the so-called "Director's Cut.")

The so-called KCOP version is the ultimate expanded edition, with the most cut footage restored. It is EXTREMELY hard to come by (I don't have it).