铭 is not 旻.
The problem is that people unfamiliar with the various CJK languages are using a mish-mash of internet sources and not knowing how to discriminate. This is especially common on SL.
Here the problem is that Japanese transcribes both these characters as ミン and certain people are evidently transcribing that into English as 'min'. In other words they are going from Japanese > English instead of Chinese > English. Chinese has both 'min' and 'ming'. Japanese has only 'min' (though it sounds rather like 'ming' when they say it!).
To see the problems Japanese have if they try to transcribe Xie Yimin's, I have collected the following variants: Sha Iimin, She Imin and Shei Imin (not to mention the English variants Hsieh Yi-min and Hsieh Yi Min, the latter giving rise to Miss Min etc.
It is definitely Wu Yiming with a G by the way. And a reminder that she is the youngest female pro in Chinese history. She will be 16 in December, so has a couple of years on Sumire, who turned 13 in March. Their Korean counterpart, Kim Eun-chi will be 15 later this week (27 May).