We are planning a migration of three planning apps to the newest version:
1) What is the best way to go about it
2) We want to also migrate our AIX cubes to Windows, the reason for that is the high maintenace costs of the IBM machine and also we do not see any performance gains.
You could try using the upgrade wizard to upgrade the planning applications directly from 22.214.171.124 > 126.96.36.199 or go down the official route of 188.8.131.52 > 184.108.40.206 > 220.127.116.11 or 18.104.22.168 > 22.214.171.124 > 126.96.36.199
Alternatively you can try and see if LCM can migrate through you may hit issues, there is meant to a patch released to enable LCM from 188.8.131.52 to 184.108.40.206, 220.127.116.11 and 18.104.22.168 of planning are very similar.
For the data you can export from the Essbase databases and then import.
I am sure if it will work or be supported if changing OS and using the staging tool so use it at your own risk, the safest and cleanest option would be to export the data.