Thanks for your help! Knowing the patronymics helps me to break down the names.
I'm still a bit confused as to what are given names and what are surnames? I'm guessing that in example (1) Aergul Lawhir is the given name and there is no surname; he would just be referred to as Ap Trffyn instead of having a surname. Do you know if I'm on the right track here?
Thanks,
Sara