Public Holiday on first day in Tokyo

It will be a public holiday on our first day in Tokyo. Will we be able to exchange our vouchers for JR Passes that day or will the offices be shut? Also can you tell me if we would be able to go up the free Observatory at the Tokyo Metropolitan Government Offices or will that be closed? Finally, I know the best days to see the girls in the Harajuku district is on Sunday but wondered if they would be around that day as there is no school? Thanks for any info.

Spuds,

JR offices and the Tokyo Metropolitan Government Building observatory should all be open on public holidays.

I don't really know about Harajuku, but there could be a smattering of girls/boys in cute clothes hnaging around on public holidays as well as Sundays.