Hello Michael,
As I wrote, most census records came from Findmypast (Findmypast.co.uk), but other websites such as Ancestry.co.uk would have most of the same census information. There are free IOM census indexes under "Research" on the IOM FHS website (www.iomfhs.im).
The 1911 census has John GICK widower aged 61 as having been born in Inchmore Dublin, which supports the 1891 census of Devonport which has his birthplace as Dublin, Ireland, and his wife Anna as born in Meath, Ireland. I wrote that I think this information is too specific to have been an error in which the enumerator wrote "Ireland" instead of the "Isle of Man".
This means that the Gick family in the Isle of Man was not your one, because John Gick was born in Dublin, Ireland - and you are very lucky that the actual area has been given. The 1911 census was filled in by the head of household himself (John Gick), and he wrote that he was born in Inchmore Dublin. I've now had a look at the actual scan, and daughter Aileen Teresa's occupation was Father's Housekeeper (not Mother's). John also filled in the marriage information which was crossed through because it was meant for the wife to fill in, and he was a widower. He had written that he had been married for 34 years, and had 9 children with 8 children still living. His house had six rooms (not counting bathroom etc.).
Obtaining an official copy of the marriage cert is crucial for you to be able to go further with your research. The reason you have gone off course is because you have been looking for what other people have written rather than systematically checking all that can be found in official records (civil registration, census scans of the original records, wills, etc.) for each generation before moving back to the one before.
Other people's research may be helpful if accurate sources are given for each entry, but more often it is not. Many people compile family trees copied from someone else's tree who may have guessed/invented items, and there were a lot of people with the same names living at the same time, and often in the same place!
You may end up finding that you are related to the Gicks in the Isle of Man, but at the moment (and until you have obtained those official records to confirm your line) all the evidence is showing Ireland.
Sue