"When I connect the new PC will I be able to configure its IP Address as I have for the other 4 devices which are connected"
Yes - I can't see any reason why it won't work.
"I know that the switch does not have an IP address but would have thought it would show up on the Interface information in the router."
I wouldn't expect the router to show the switch. If you want to view all the other connected devices then they should appear in the router's DHCP clients' list.