Desktop Search - with more features than Spotlight?

I don't know of a third party solution, but I do know that Spotlight can do all of those things, except for #6, but that's more of a function of Word than Spotlight.

DEVONthink can index specific folders, and supports advanced search operators. It supports most common types of file, including Word documents.

It builds its own search indexes (a DEVONthink database can support Spotlight – screen shot below – without relying upon Spotlight). Search is pretty fast. Results are shown within the application.

Pro editions allow multiple databases. Each search is restricted to the open database(s); you can have separate databases indexing different logical collections of files.

Screen shots from a first run of DEVONthink Pro Office 2.8.11 on pre-release macOS Sierra:

Try Alfred or Quicksilver

Those apps are amazing :)