I do have an adamant alolan Sandshrew yes. Sorry for the late reply, beeen playing Monster Hunter this weekend.
Mew's nature is quirky.
I also have a shiny Chansey with Timid nature.
Actually I'm about to evolve my second Melmetal in pokemon GO so I don't mind trading one for a Mew.. what nature is your Mew?
The melmetal I have is Lv100 adamant with almost perfect IV, a few bottle caps and you are golden
Can you offer Melmetal to keep? I can offer 3 shinies (raticate, mankey, gloom) or Mew in return.
I understand if you don't want to lose him, in that case I'll install pokemon go and start the grind. Good day to you!