1) Does Physical/Logical Standby DB work between 2 different patches of same oracle version? i.e. 220.127.116.11 and 18.104.22.168
2) If you are planning to set up the DG(11gR2 Physical standby) in Max Performance mode, would there be any advantage in adding SRL?
3) Does number of RFS process on the standby database(22.214.171.124) depend on LOG_ARCHIVE_MAX_PROCESS?
1. The simple answer is no. They must be on the same patch set. Think of it as 1 database in the same mode.
2. Yes. Standby Redo log will still buffer data making it less likely to lose data in a failover for example.
3. No the control archive processes. See figure 6.1 in the link below.