If it was easy it would'nt be so much fun!
I think the confusion arises because there appears to be 2 families with the same names (John & Maria). There is a family who are better match in the 1881 census (also on LDS web site). They are living at St. Georges Street, Everton, Liverpool.
I totally agree with Frances about getting provenace on the information obtained thru the web etc. There is a lot of guesswork out there and it is not always portrayed as such. An example of this is the IGI on the LDS website. Any extract that gives dates as "About" or the source of the information does not relate to a parish register etc can almost be dismissed out of hand.
I would suggest you approach Brian Lawson to find your family in the 1861 & 1871 census. It should help with Rebecca's age, John/Maria's ages and place of birth etc.