Every time Jesus is referred to as "God" he is being called "Immanuel".
In regards to what we knwo about Christians, we know as much as we know about other relgions at that time, perhaps more even.
We have the writings of christians and even those that wrotes against Christians or were mere observers.
A good example is:
Pliny the younger:
They affirmed, however, that the whole of their guilt, or their error, was, that they were in the habit of meeting on a certain fixed day before it was light, when they sang in alternate verse a hymn to Christ as to a god, and bound themselves to a solemn oath, not to any wicked deeds, but never to commit any fraud, theft, adultery, never to falsify their word, not to deny a trust when they should be called upon to deliver it up.
Truth be told we don't have much mention of what types of people the Christians were other than by their own writings, which is at least indicates that they didn't do anything overly notworthy in a bad sense, unless you take for real the view that Christians set fire to Rome, which NO historian does of course.