I came up with three 7x54mm variations, a Finnish, French and the M-S.

Just copy and paste the calibres as I wrote them above into Google and do a search, that would be the best way to see for yourself.

You might be right about the 7x54mm just being a wildcat to freshen up the bores of worn out 6.5x54mm rifles, but the Greek one might have a different purpose and history, unless it too is to just clean it up to a .30 cal. The Greek one is listed in Wikipedia, but no technical data or history on it.

I was hoping somebody out there would have reference material on either one, or at least something in a wildcat/cartridge conversion manual with some history.