Sorry for jumping in late, but work has been intruding on my following this thread.
The origins of 4800-8N1 stem from the NMEA specs for shipborne autopilots, where they standardized the interface. Computers were primitive and stupid and you had to have something to standardize on, so they made one.
I'll try to look at the rest and see if I can muddy the waters any more, after Saturday evening. I've got a Cray that's dyspepsic, severe weather happening (that my group's working on... on the Cray), and a class to teach tomorrow where the slides aren't done yet.