I think the best thing for the moment is to forget about John and Mary Ann, because it seems to me that they are a red herring and they are serving only to cause confusion, and concentrate on the John Wigley you are actually related to.
As I understand it, and for the benefit of others who may be trying to help, the one you are interested in was born in England but not in Warwickshire some time between 1791 and 1796 (adults' ages were rounded down to the nearest 5 years in the 1841 census, so he could have been anything from 45 to 49 on 7 June 1841, assuming his age is recorded correctly).
He married Harriet Porter, daughter of Nathaniel and Ann Porter, who was baptised in Birmingham on 31 August 1803, in Birmingham on 5 January 1824, and they had at least five children. I take it that you have seen the original of the marriage record? Does it tell you the names of John's and Harriet's fathers? Does it give the names of witnesses?
The 1841 census lists
John Wigley, 45, clerk
Harriet Wigley, 35
John Richard Wigley, 15, gun maker apprentice
Robert Nathaniel Wigley, 14
Richard Joseph Wigley, 9
George Henry Wigley, 4
Edward Anthony Wigley, 2 months
Isabella Davis, 15, F[emale] S[ervant]
Richard's birthplace looks peculiar (could just be a 'ditto' mark), but all the rest of the family were born in Warwickshire.
There are several gaps that could be accounted for by a child who died young.
Looking at baptisms, there were at least six:
John Richard, born 14 Feb 1825, baptised 15 March 1825
John [sic index] Nathaniel, 8 December 1826, 9 January 1827
Thomas Hugh, 11 June 1829, 25 September 1829 (presumably died before 1841)
Richard Joseph, 14 August 1832, 27 November 1832
George Henry, 3 March 1836, 12 August 1839
Edward Anthony, 31 March 1841, 3 May 1841
all baptised at St Philip's, Birmingham.
Have you seen the originals of all these baptisms? Were any witnesses listed? Who were they?
(There's also a Mary Ann, born 9 August 1835, baptised 27 May 1836, but she cannot be a sibling because George's birth is too soon after hers. I note in the 1851 census a Mary Ann Wigley, aged 15, with father John Wigley, 36, master carpenter; mother Harriet, 32; and siblings Samuel, 11; Albert, 9; Harriet Isabella, 7; Pasumela, 6; and John, 5. This couple were John Wigley and Harriet Suter, married in Handsworth in 1835.)
John Wigley, aged 46, died in Birmingham in the March quarter of 1842, aged 46. Assuming that his age on his death certificate is correct (who registered the death?) he would have been born in 1795 or early in 1796.
The IGI at FamilySearch lists 9 John Wigleys born in England in 1795 and 1796. There is one whose father was Jonathan and one whose father was David. As John apparently did not name any of his sons David or Jonathan, it is less likely to be these than to be one of the others, but again (a) he could have had a son named David or Jonathan or both whose baptism is not in the IGI or (b) he could have fallen out with his father and deliberately not named a son after him.
A full records search on FamilySearch produces 80 references to John Wigleys born in England 1795 or 1796, but even though I included a death year of 1842 in the search it has returned references from the 1851 and later censuses! Although you could use the places of birth in later censuses to eliminate some of those whose birth or baptism is listed. Again, FS is not 100% comprehensive or 100% accurate and it is possible that your John Wigley's baptism, even assuming a record of it survives, has not made it to FS.