Ground pour under ESP8266 12-E
You should not pour ground under the antenna area, leave both layers free from pours and traces in the area immediately below the antenna; you do not want bits of copper coupling to the antenna. A ground pour under the non-antenna portion of the ESP-12E is fine, although I would avoid pouring on the top layer, as there is a (very slight) possibility of a short if both masks (on your board and the ESP) were to become damaged in the same spot and make contact. However, this chance is very slight, and if you want to pour under the ESP on top, it's probably fine.


  1) Does the ground pour affect ESP12-E?


Yes, when it's under the antenna.


  2) Is it safe to have ground pour with signal traces on it?


Sure, most ground pours have traces in them.


  3) If it's safe to do 1 and 2, I should pour ground on bottom too, right?


Yes, just not under the antenna.

You should also not route traces under the antenna, and again, if it were me, I wouldn't route traces on the top directly under the device, as they would be very close to the ESP's traces (only separated by two layers of soldermask) and could be interfered with.