About changing the admin name, you have to enable the Editable screen name option in Administration->Users settings. Then you can go to the Users->Your User->User tools->edit profile and you can choose the name you want.
About changing the language, just edit the settings_local.py file (/opt/bitnami/apps/osqa/settings_local.py) and change this line
LANGUAGE_CODE = 'en'
LANGUAGE_CODE = 'es'
After that, restart apache
sudo /opt/bitnami/ctlscript.sh restart apache
Hope it helps!