If a token is given undying, does it work? I know that tokens don't go to the graveyard when they die, but does that negate undying?
For instance zombie token + {mikaeus, the unhallowed} or undying evil.
It goes to the graveyard, vanishes, but still triggers the undying but no longer has a target
Unfortunately, they don't. No matter what, tokens exile the moment they move zones. They still trigger GY entering effects, but do not go there. Ever. For more, read below link where topic has been discussed previously:
http://imtgapp.com/forum/index.php?topic=1769.0