The JR Pass isn't very hard to replace. It is impossible. Japan Rail has a clear policy that if you damage, lose, or erase your JR pass they absolutely will not replace it. Additionally, you can not buy a new a JR Pass until the old one has run out. This was clearly posted in several JR Shinkansen Ticket offices while I was in Japan for the beginning of this month.
for reservation of seats for different legs of the trip, is it most recommended to go to the office to do this? for example, tokyo-osaka,osaka-takayama-nagoya-tokyo? can we reserve the seats for these legs of trips if we know the train timings?
When I look up one destination to another it shows a jr train then a non jr train, will I need to be also buying regular train tickets to complete some trips?