Hi
Going back to the O'Neills.
John O'Neill was an Army pensioner.His pension record is on FindMyPast.He signed up 1865 and left 1869 before being called back until 1885 .That's why he moved around so much.
Unlike the usual records of the time his pension record is quite full ,a description ,mention of his 1879 marriage at St josephs Guildford to Sarah Breech ,lots of postings and times in prison for his misdemeanours .Place of birth in the County of Cork at Ballyhead ,Kinsale .Apparently he drank a lot.And over stayed his leave.
Well worth taking a look .I can pass a copy on if you haven't got FindMyPast.
Ciderdrinker