Hi Steve,
Been digging around on internet and found the following;
1) The car charger appears to connect to the usb cable and this is where the power input comes into the unit.
2) Yeah, seems to be correct but looks like you may need the "optional" battery back-up which seems to have a 5v and a dc5v input for wiring in.
3) Can't find much about the software at the moment, check out the link below though - has a rather neat looking demo.
4) US Stock so looks like you would need a travel adapter.
5) usb is certainly used for power input but I guess for setting up the quick dial numbers etc?
The link below has some more detailed info - hope this helps :)