As usual the RootsChaters are on to the nub of the problem.
The Miss Fynney at the wedding is in fact born Maude Louisa Dixon on 1st April 1880, I have a copy birth extract, her mother is shown as Susan Dixon formerly Fyney (sic) of Hawfield Cottage, Ludworth Derbyshire. The birth took place at 5 Goldie Terrace, Douglas. The father is shown as a agent name of Alfred Dixon.
Maude Louisa lives with her mother, Susan until she dies but does not marry herself.
The boy Augustus Frederick born 1871 referred to in these post is recorded as Dixon but due to his earlier birth date there is no birth certificate. He is shown in the index as Dixon. He goes on to marry and shows his father as Augustus Caesar Fynney. Both children are shown on subsequent census as Fynney.
There are other children born Dixon in the IOM and are obviously brothers and sister to these two they are buried at Brandon but the grave is unmarked.
The nub is that Augustus Caesar Fynney was married to a Jane Morris and on the census of 1871 they are in Manchester with a "visitor" Susan Jones born Bristol aged 21. The boy Augustus Frederick born 1871, was at this census in the IOM with the Kelly family and he is shown as Dixon.
Similarly in the 1881 census Maude Louisa is shown as Dixon with the Cowin family in the IOM. Augustus Caesar and his son together with visitor Susan Jones are at Empfield House, Ludworth where she is a "visitor". Jane his wife having died in Hayfield in 1878.
I have not been able to find a record of a marriage between Augustus Caesar Fynney and Susan Jones. Augustus Caesar dies on 6th March 1884. Susan reamins on subsequent census as Fynney with her children, her will is in the name of Fynney and the Fynney family leave bequest to her in their wills where she is referred to as Fynney.
By creating this post I was attempting to establish the connection of the "Fynney's" and the IOM.
A look at the wedding list shows a Mrs. T. Cowin giving a butter dish, could this person be the same Mrs Cowin who looked after the baby Maude?. Also there was a photographer at the wedding who took them all.
This is a bit of a Saga so I didn't put it all down at the start as it is so confusing.
Now of course you are all on to it!!
Boy Scout