Can I create JDE BSSV (Business Services) for REST based services? If yes, then how? In what way it will be different from SOAP based?
Within Oracle SOA Suite, Oracle Service Bus would handle the REST side of things, which in turn would call the JCA adapter to talk to your JDE backend, or vice versa.
Checkout the JDE adapter docs - http://www.oracle.com/technetwork/middleware/soasuite/documentation/jdewardsweb-1954164.pdf
and the OSB Docs - HTTP and Poller Transports - 11g Release 1 (188.8.131.52)
OSB 184.108.40.206 introduced additional REST support, so I'd recommend using that version onwards.