Many players may already know this trick, but in order to get an Umbreon, name any male Eevee Tamao; or to get Espeon name any female Eevee Sakura, then completely exit the game, make sure it’s not running in the background, and relaunch the game.
I have photographic proof that this trick works. Got both Umbreon and Espeon on our first attempt.
To see the pics or read more about the trick, please refer to my guide at https://mediacraft.rockuapps.com/articles/how-to-get-gen-2-evee-evolutions-umbreon-and-espeon-in-pokemon-go