1. I don't recall my first VRDB generation taking very long at all, though my system doesn't have that many programs installed on it.
How did you start the VRDB scan, was it by generate now, that should be the quickest ?
A little about your system would be helpful, like OS, CPU, RAM, how many hard drives, qty of data, etc. ?
2. There should be no conflict, though I feel there are better free firewalls than zone alarm.