I deleted my old container since I did various stuff with chown and chmod and created a new one so I can make a fresh start. I executed lxc exec sift -- sudo --user ubuntu --login and I got:
sudo: error in /etc/sudo.conf, line 0 while loading plugin "sudoers_policy"
sudo: /usr/lib/sudo/sudoers.so must be owned by uid 0
sudo: fatal error, unable to load plugins
Again similar to what I got before but with a few more stuff into it.