C # - get all open tabs to view in all firefox instances

How to get URLs of open pages from Chrome and Firefox?

How to get URLs of open pages from Chrome and Firefox?

http://hintdesk.com/c-automationelement-left-click-and-send-keys/

How to check if a website is open in a web browser?

etc...

everything is crashing. Either they only return the topmost open tab, or they don't work at all.

I need to check and see if firefox opens at all to the url, if it then refreshes and focuses that tab / url if not open firefox on that page.

This is not a firefox addon or anything really related to firefox. This is my browser, so I want to use it. This is all about avoiding sequentially opening the same URL every time I start my application.