Official Facebook messenger and Instagram is available for Tizen OS. It is surprising and sad to see that OS which is no where near 1% got full featured app while windows phone version has been stuck in beta for ages.
Source: Official Facebook Messenger and Instagram Apps Launched for Tizen-Powered Samsung Z1 - Softpedia
Source: Official Facebook Messenger and Instagram Apps Launched for Tizen-Powered Samsung Z1 - Softpedia