1) the following Document “Deploying Avaya Aura® Communication Manager on VMware® in Virtualized Environment” for CM release 6.3, on page no. 23 and 24 that You can deploy the Communication Manager OVA Release 6.3 using VMware vSphere 5.5, VMware vSphere 5.1 and VMware vSphere 5.0.
https://downloads.avaya.com/css/P8/documents/100171633
If you wanted to upgrade to VMware to Esxi 6.0, we recommend the CM to be on version 7.0
If you wanted to upgrade to VMware to Esxi 6.5, we recommend CM to be on version 7.1
2)For AAM 6.x only supports VMware 5.0, 5.1 and 5.5.
If you wanted to upgrade to VMware to Esxi 6.0, AAM should be on 7.0.
AAM version 7.0, SP 0 is not recommended as of now we see there are known issue.
AAM development team is working on building a patch to fix these issues for CM 7.0 SP1. Avaya Messaging will communicate when the fix is generally available.