I think you've got the right people.

I started out with the 1881 census, indeed Fred and James are there - Fred born Bristol, James born Birmingham (apparently). The father says he is 39 there - but I am thinking that the original date of 1837 is correct as in 1891 he would have been 54 (45 back to front?). Oh bummer, I just noticed that the birth record I was looking at was for "Davies"...

Ok, so perhaps he was born in 1841 after all. (Back to looking)!
The info on naughty William makes sense then as well. He later went on to be a 'dock labourer'. Must have learned a thing or two! Some of his own children (my grandmother and her siblings) - they had 2 Alberts (one was a twin and died), William, James and my gran Violet's middle name was Sarah. (There are lots of others too).
And the marriage one - yes, I'm definitely sure the PULLEN lady is the right one.
I just saw your latest post regarding Samuel remarrying... wow...could well be. Ooooh... the plot thickens!