Irish Catholic Parish Registers: Baptism Questions

As I explore the Catholic parish registers recently put online by the National Library of Ireland, I've realized that I don't know as much as I should about the conventions that would have dictated how they were created. In that light, here are the questions that are piling up as I browse:

• Was it standard operating procedure for an illegitimate child to have only one godparent/sponsor at baptism? I've seen this appear to be the case on two occasions, in two different parishes: different dioceses, different counties, different decades.  

• How common was it for the father of an illegitimate child to be publicly known? Most seem to have a father listed, even when that father appears to be married to another woman. What mechanisms were in place to discover the father of an unmarried woman's baby?  

• If a married woman was a godparent, would she be recorded in the register under her maiden or married name?  

• Were parents ever recorded by their titles rather than their names? (Specific to my family: What English-language name (or title) could be recorded as Mayistri?)

If I can find the answers to any of these questions, I hope to write some follow-up posts to provide as much context as possible.

What sources would you recommend to learn about the context surrounding birth and baptism in 19th century Ireland? What do you find yourself wanting to know about the Irish parish registers?