I only wonder about one thing (and I don’t have the answer): you start out addressing multiple people but each line afterwards addresses one person.

Yes, it should be 2nd person plural,
… libh (instead of leat)
… ar bhur n-aghaidh (instead of ar d’aghaidh)
… ar bhur ngoirt (instead of ar do ghoirt)
… le bhur dtaobh (instead of le do thaobh)
… bhur nDia (instead of do Dhia)
… sibh (instead of thú)