Wood Style is exclusive to Hashirama, due to him being Ashura's transmigrator and due to his strong chakra that can withstand overwhelming and chakra-taxing kekkei genkai.
Others are just borrowing his powers (Danzo, Yamato and Madara) and look what happened to Danzo, he almost turned into a tree because of Hashirama's dna.
As for Yamato, he's just using a lesser power of Hashi's Mokuton.
Madara is understandable because he's a transmigration of Indra's and that probably enables him to control Hashirama's Mokuton properly.
Besides, they all have one thing in common; they're using Hashirama's DNA.
So wood style is undeniably exclusive to Hashirama.
Mei probably don't have the chakra nor the ability and the proper means (hashi's dna) to gain Mokuton.
p.s i forgot obito, and yeah sure, mei would love dem woods !!