I'm not sure why this is an issue since all of Christendom believe YHWH (Jehovah in English) was God's name. This isn't a witness issue.
The founding fathers of America believed Jehovah was God's name. Thomas Jefferson did. George Washington did. Abraham Lincoln did. Jehovah is used in thousands of great pieces of literature throughout history to represent God's name. Go to Saint Mark's Cathedral in Venice and YHWH is right there on the tile when you walk in the building on the right hand side. Hemingway always referred to God as Jehovah.
It wasn't until the witnesses started really pushing the issue to differentiate themselves from all the other Christian religions that they all started pulling back on the use of using YHWH and Jehovah.
Jehovah and YHWH were around long before the Jehovah's Witnesses. They just used God's name like everyone else was doing in the 19th Century.
Or you could just ask a Jew to take some time out of his very Jewy day and he'll let you know what God's name is (so long as it's not in public, because they are not supposed to say it out loud).
But then again I'm not sure what the arrangement of the letters of God's name is supposed to prove. It's different in almost every language. If the text uses the original tetragrammaton then that's what should be translated. What vowels you use in between those letters is simply a metric of whatever language is being used. I think sometimes we overthink these things.