Mimicking Birds - Subsonic Words Chords & Tabs

According to live performances, it seems Nate plays the chords like one would play Em 
and Am in standard tuning, except he clearly plays in a lower tuning.


As far as i can tell it is CGDGBD
[ Tab from: https://www.guitartabs.cc/tabs/m/mimicking_birds/subsonic_words_crd.html ]
    A11?    Am9/A11?
D|---x---------0----|
B|---0---------0----|
G|---0---------2----|
D|---2---------2----|
G|---2---------0----|
C|---x---------0----|

The strum pattern is basically down down up, down down up, down up (listen to the song 
for clarification). I would love some help figuring out the leads and bridge!