12C is certified with AIX 7.1
So if you upgrade your database to 12c (184.108.40.206) first, then it is okay to migrate to IBM AIX 7.1 64 bit.
That is, upgrade your db in place first, then migrate to AIX 7.1.
However; thr right method may also change according to your migration method.
That is; if you are using exp-imp for EBS-db migration, then you can do the db upgrade and migration at the same time.
For example you can migrate a 220.127.116.11 db using exp imp to 12c directly. (18.104.22.168 may be running on AIX 6, and 12c may be running on AIX 7) This way you do the db upgrade and migration(+OS upgrade) at the same time.
Export/Import Process for Oracle E-Business Suite Release 12.0 or 12.1 Database Instances Using Oracle Database 12c Release 1
The source (export from) ORACLE_HOME directories must be Oracle Database 12c Release 1 (12.1.0), Oracle Database 11g (11.x), or Oracle Database 10g Release 2 (10.2.0.5). The target (import to) ORACLE_HOME directories must be Oracle Database 12c (12.1). You may not downgrade using export/import.