Excell and McDevitt Families of Australia

I am researching my ancestors on both parent's side.
Earliest information I have to date is when these ancestors first arrived in Australia.
Major names are McDevitt (could originally have been McDivitt)
from Londonderry, Ireland.Duffy from Sligo, Ireland.Satterly
from England,Hackett from England.Marsh from England.Holzworth from Germany,