I can tell you from my perspective "night" or "late night" is just that. Midnight, is a specific time that only refers to it being 00:00, or 12am. come 00:01 it is now early morning. So midnight is exactly that, 00:00. I can also say that5 when I lived in Germany it was the same thing. Hope that helps. I work in aviation and fly a lot so time is very specific for us.

Midnight - not midnigt - is a very specific time - it is 12.00pm - the minute that marks the border between one day ending and the next starting. Late night is no specific time, and depends on the context and the point of view of the person using the phrase. Late, of course, is comparative - you can only be late, compared to something - late for a meeting, late home (i.e. after the time you said you would be home). So 'late' is always going to depend on the context. So a 'late night' could refer to being up well past the time you normally go to bed - your 'late night' could be someone else's normal time. A 'late night party' could go on until the early hours of the next day - well past midnight. I don't know if there are cultural/regional differences. I do remember saying I would meet an American friend 'at midday' - which to me is a very specific time, i.e. 12.00 noon - and she asked what time? I was quite confused but it seems that midday to her didn't mean what it meant to me- so who knows?

Midnight is 12am. 12:05am is five minutes after midnight. 11:55pm is five minutes before midnight. Late night is just a time very late at night. Exactly what late is depends on the person.