Always on availability group removing nodes

We have a SQL 2014 enterprise with 4 node availability group database with 2 Synchronous commit , 1 read only Asynchronous for reporting and 1 DR asynchronous. Due to space shortage we need to remove some nodes. Since the reports points out to the Asynchronous reporting server can we remove 2 nodes ( 1 Synchronous replica and 1 DR) and make the Reporting server in Synchronous mode and keep it read only. The cluster will then have 2 nodes both in synchronous mode with 1 disk witness for the quorum. This setup will thus have no Disaster recovery server as it is temporary . I will appreciate if someone can advice whether I can have this setup or if there is a better work around.