And this is the website that has the church recordshttp://archives.maltadiocese.org/Archives.aspx
Melliaha is not on there, they are still microfilming everything in the vault before they begin moving onto the other parishes. So the best thing to do is to order certificates, this will enable you to do the direct line but not siblings - although if my memory serves me correctly death certificates list children.
Also bear in mind that a baby will be given several names and the parent will choose one name to call them by not always their first given name. And sometimes even that name interchanges.
So for instance I was working on a line last night and found two other children, the father was christened Raymondus Aloiysius Joseph Andreas but married as Andreas, on one of his childrens baptism records he was Joseph on the next child he was Andreas again. Lucky the mother was the same which was why I was able to spot them, missed them first time round because of the father's name change.
So just be aware that name are sometimes interchangeable.