I believe Mary Street (possibly Mary Streak bapt. 31 July 1796) married shepherd John Smith on October 21st, 1815 at Ipsden.
Son Henry was bapt. Aug. 4 1816, son Joseph on Mar. 14, 1819 and daughter Anna (Hannah?) on Nov. 24th, 1822 - all at Ipsden - with Mary and daughters Anna and Sophia appearing on the 1841 census living together in the hamlet.
I can't find a burial record for John in the surrounding villages, but there are a number of candidates on FreeBMD in the Wallingford area. Nor can I find a baptism record for James Smith, although 1813 would put him before Mary's marriage if he was their son.
Mary's second husband William Harris is shown as having been born in Ensham on the 1861 census which is at the other end of the county. I am not sure you implied a link between Charlotte Harris and William Harris, but Charlotte Harris's daughter Anna was baptised at Checkendon on Nov. 7 1858 and her parents were recorded as being John Henry (a Baker) and Charlotte. Charlotte is still shown as married and living in Hammersmith in the 1871 census, although in both Goring and Hammersmith husband John doesn't appear on the scene.
For all that it is quite possible that James Smith is the son or a close relation of John Smith's family, but in the absence of a baptism record it is going to be quite difficult to prove. It doesn't help that there are least three Smith families living in Ipsden in the early 1800s.
Some additional information:
James Smith shoemaker, Ewelme married Elizabeth Bryant at Woodcote chapel on 24 Nov. 1838. Unfortunately, no father is show for James.
In the 1841 census it shows them living in South Stoke with James's date of birth shown as 1821, although we know that can be inaccurate. (Source Citation: Class: HO107; Piece 880; Book: 10; Civil Parish: South Stoke; County: Oxfordshire; Enumeration District: 21; Folio: 12; Page: 19; Line: 4; GSU roll: 474573.)
Something of a ramble I'm afraid, but I hope some of this is of some use!
