p.

Why is there a period after the person's name in this address?

Also, should we transcribe the stamp or postmark?

Good questions! I have no idea why the lines would end with a period, though from the few I know, I suspect postal workers see an incredible range of oddly formed addresses.

With regard to postmarks and stamps, we don't have a rule in place (yet), so ignore them for now. But you've given us something to think about, since the postmarks especially contain potentially useful information for researchers - since your eyes have been on a much wider array of methods & formatting decisions than ours, maybe you can offer insight into if/how others handle them?