I think you should check the Exadata version again as 188.8.131.52.17 is not a valid release of Exadata. However, the Exadata version isn't relevant to your question. While it would be best to match all versions (Exadata, grid infrastructure, RDBMS), the primary concern for supporting data guard would be the RDBMS version and patch bundle. You didn't include the bundle patch version (184.108.40.206 BP17 perhaps), but it would be good to have those match to avoid any issues that may come up due to differing versions between primary and standby sites.
It would be good if you share the current RAC setup (e.g. how many DBs etc.) you have at site1.
You need to decide whether you want to have the RAC Standby database or single instance Standby database.
What kind of data guard do you want to have, Physical, Logical or both etc.