I can't find screenshots or descriptions of that either (but it doesn't really say much either way - I couldn't find much about the spellchecking at all). But re: colors, a lot of applications would open their own screens and set their own palette, so the Workbench palette isn't necessarily relevant.
Indeed, no relevance at all. Sorry rob74, that's a misunderstanding of how large applications most often tended to work on the Amiga. They didn't generally open a window on the Workbench screen, they opened their own screen. The keyboard shortcut <Amiga key>-<M> cycled between them. A word processor's screen could then have 16+ colours.
No problem! My recollection is a bit hazy, and I'm not active enough in retrocomputing to refresh it. I was aware that applications could use their own graphics modes, but I wasn't aware anymore just how often "productivity" software did that too. But of course, it made sense, since the Workbench screen was limited to 4 colors (in order to save memory, I guess, especially the precious "chip memory" that was accessible to the custom chips), and on their own screen they could use a whopping 16 colors :)