1. How can I synchronize SUP/MSFC configuration across Cat 6500s
2. How can I verify the synchronize is successful
3. What all elements are synchronized. For e.g. vlan-groups, SVI I believe are not synchronized.
If you mean between 2 6500 chassis's and you are not running VSS then most of it is a manual process i'm afraid. There are no commands to actually write the configuration across and you wouldn't necessarily want to as one 6500 chassis may well have different ports in different vlans than other.
Some of the service modules do allow synchronization across chassis's eg. the CSM (Content Switch Module) which can write it's configuration from the active switch to the standby switch (active/stanbdy used here in CSM terms only).