Regulus may not care very much for her, being that she is halfblood (old habits are hard to break) and she's a part of the Ministry. However, I am always up for excuses and plotting!
Eddie, on the other hand, might be a tad more friendly. She isn't pleased with Greta's disdain for the Muggle Ministry/Muggles in general, but would probably be forgiving nonetheless. If they should ever meet, Eddie would probably spend her whole time interrogating Greta about the secrets hidden by the Ministry -like their experimentations on unicorns and where they're hiding Hitler, etc.