She would have been a lower top 10 BW probably.
Ronda - subs Coenen
Tate - we know already
Nunes - TKOs Coenen
Shevchenko - decisions Coenen
Holm - decisions Coenen in a boring fight making 100 ish sounds lol
McMann - probably decisions Coenen, might be able to force a sub on her ala Davis
Zingano - interesting actually, but favor Zingano
Pena - same as Zingano
Davis - tough pick, 50/50 as long as Coenen wasn't too past it
GDR - might actually take Coenen due to GDR lack of grappling
She should be favored over the rest of them from Carmouche on down... again, assuming she wasn't too past it by the time she fought them. Some of the ones on the above list didn't appear/rise until later so she could have been close to the top 5 at some point. Edit: Forgot Pennington but that's really hard to call given Pennington struggled against Bethe and then beat a soulless Tate.
Coenen was more of an old breed (W)MMA fighter I think, a BJJ fighter with decent striking but not much wrestling. The modern grapplers would likely outwrestle her and the modern strikers would be hard for her to get down.