We are migrating to WAS 8.5.* and PRPC 7.1.7 is supported. Are you asking us to do a fresh installation of PRPC 7.1.7 on the new WAS and then migrate it to PRPC 7.2.2. Please correct me if I got you incorrectly.
Why are you looking to do a fresh install and then import your application and upgrade? Since you are already on 7.1.7 you should update to 7.2.2. You will need to update the framework versions as well to versions that work on 7.2.2.