1) No, it doesn't. It will single out gun
and won't even recognize Occam's, let alone pair it with razor
2) Yes, you can nest lookups and use the back key to return to previous searches.
3) I have a Kindle Keyboard and find it slightly tedious to cursor my way to the word I want to lookup. I have never tried the Touch but I imagine it should be much quicker to directly highlight the word to lookup.