Should 120 or 320 dinars be donated from money earned from a translation project that was not up to standard, and should this money be spent on things like repairing restrooms instead of feeding the poor?

If you fell short in your translation work and did not perform it as required, then it is obligatory upon you to return the right of the employers or seek their forgiveness. If you are unable to do so, then give it as charity on their behalf to the poor and needy, or spend it on public utilities such as mosques and hospitals.