Mary, some amendments to what you have stated, and to bring it more up to date:
Census, if you read the instructions (for 1851) it tells the enumerator to copy exactly what the head of household wrote in the schedule. The wording you use: " it is important to pigeon/dove cote peope into three boxes, pre-working, working age(if they were employeed if they were working, and old age" has nothing to do with instructions to enumerators....easy to see why, the church was still doing most of the "social welfare agency caring, but the crown understood that it would eventually fill that role, [No, the state did not assume such things. By 1845 the Poor Law in Scotland was already in operation, making care of the destitute a civil matter; but it was 1911 before the first Old Age pensions started, and the unemployed were not included in civil care until 1930.] so large numbers of chilren in schools might need tax money, working or not-paying taxes and keeping account of if the tax base was increasing or decreasing, and finally elders who would eventually need increasing help, was and still is an important issue.[BUT this is social policy, and not in itself a matter for the census enumerators.]
Nobles who had very little care of their tenants, didn't want to give to the poor, or set a prescient where they might be pressured to give more.
The word "Nobles" is incorrect: it should be landowners - most of whom were not of the nobility. In church care for the poor, it was the Heritors were were financially responsible, and they were all landowners. When the state took over, the (civil) Parochial Boards had the power to impose a levy, if the voluntary system failed to operate properly.
the early census 1800-1831 were tallies, and original sheets have no family names. !841-1851,enumerators were told to move age + or minus five years [No, just 1841. 1851 asked for exact ages]. 1841 just asks if born in Scotland. [NO, it was whether born in the COUNTY] So the government could care less for next of kin. The other religions are not centralized, but it is important to at least look at them. [Not entirely accurate. ALL the R.C. registers have been sent to Edinburgh to be copied and sent back, or retained and copies sent back, and these are indexed. Other denominations are partly centralised, but not indexed nationally.]