Hi Angie
Charles was Alfred's great grandfather, so (I think) that makes you a second cousin (once removed) of the famous director, yes?

I've currently got the following listed as Charles' children:
- Susannah Hitchcock (b. ~1823)
- Sarah Hitchcock (b. ~1824)
- Joseph Hitchcock (b. 1828)
- Charles William Hitchcock (b. 1838)
- Mary Emily Hitchcock (b. 1840)
- Enoch Hitchcock (b. 1844)
I'm struggling to find much info on Susannah and Sarah tho.
Charles being married twice makes sense, as Sarah (2nd wife) was born around 1810 so she'd likely only be the mother of Charles William, Mary Emily and Enoch.
Going by the birth locations given on the census returns, only Susannah was born in Dedham, which makes me think Charles moved to Stratford in late 1823/early 1824. When did he marry Sarah?
I think the Catholic influence on Alfred came mostly from his mother Emma, who apparently insisted on taking him back to the Catholic church in Stratford every Sunday (even tho they lived up the road in Leytonstone, about 2 miles from the church). Dedham seems like an Anglican/Protestant village, so the Catholic influence mostly came from Alfred's grandfather marrying Ann Mahoney and then Alfred's father marrying Emma Jane Whelan (both were daughters of Roman Catholic Irishmen).
On the marriage certificate you've got, was the marriage to Sarah in Stratford/West Ham? If so, there was a William and Jane Hitchcock (both born around 1794 and parents of another Jane Hitchcock who born ~1831) living in Stratford at the time of the 1851 Census. What would fit really nicely is if this William was a relative of Charles (e.g. brother or cousin) who was already living in Stratford, as I've puzzled over why Charles would decide to make the move 60 miles southwest from Dedham.
As for Charles' siblings and parents, I've got nothing definite but there are a few candidates living in Dedham around that time. Sara Martin married William Hitchcock in 1782 in Dedham, which would be the right time to make them the parents.
Dedham seems to be a hotspot for coopers (i.e. barrel makers) around that time and several are good candidates for being Charles' brothers, especially Enoch Hitchcock (b. ~1781) and Ebenezer Hitchcock (b. ~1791) as Enoch named one of his sons Ebenezer and Charles named one of his sons Enoch (i.e. brothers naming their sons after their own brothers). Other coopers include George Hitchcock (b. ~1790). There's also a William Hitchcock (b. ~1783) who likely married Elizabeth Sharp in 1805 but who died before the first census in 1841, so I don't know what his occupation was.