Fink I am going to have a go at some of your other questions.
The ceremonial, sacrificial, 'cleanness', food laws are all considered to have been fulfilled in the work of Christ and therefore no longer applicable.
The moral laws still apply though if they are no longer directly relevant and principle behind them will be extracted and applied. E.g. as we no longer have slaves laws about their treatment would be applied broadly to employees.
Similarly, these principles would be applied to modern moral issues. On the whole people would discuss issues among themselves and read anything from written by people within the broader tradition (both Reformed and Evangelical). It is up to each individual Christian to make a final decision on things that are not definitely forbidden. Someone might consult the minister, especially for difficult or important decisions but they are not obliged to take any advice given.
Obviously some people are more confident to make their own decisions that others. There is also a fair amount of social pressure to do what has always been done.
I would say that most of the Bible is taken literally. Poetry and parables are obvious exceptions to this. There may be a bit of disagreement about e.g. the length of days in Genesis 1 but only the whole if something can be taken literally it will be.
A lot of work goes into trying to reconcile discrepancies etc. Sometimes I feel with tortuous results. If reconciliation is not possible, it will be considered part of the mystery of God but something that has to be accepted.
I remember my mother coming down on me firmly when I innocently (aged 9 or so) said about some discrepancy in the resurrection accounts, 'perhaps one of them made a mistake'.
I think most ordinary Christians are not really aware of issues around the canon. Those who read more and ministers will have encountered arguments to justify the current canon as divinely chosen through human instruments.
As far as Jesus's understanding of what is Scripture, I think it is barely considered that it could be anything other than the current canon. I think I am right in saying that any direct quotations or references in the Gospels do come from the current canon and so the question doesn't really arise for most Christians unless they are serious theologians.
As for Christians before the Reformation, they tend to get totally ignored. There is a huge gap in knowledge between the New Testament church and the immediate pre Reformation period. There are a few individual exceptions - Augustine, Wycliffe and Jan Hus spring to mind.
I think I am right in saying that even most ministers would have little awareness of the Early Church Fathers for example.
Your questions have made me realise that there are quite big gaps in my knowledge. I was unaware that Catholics considered sola scriptura as a 16th century invention.
Maybe all Christian groups spend a lot of time talking to themselves?