What is the "gospel" in OT according to the Calvinist?

This question is following my question before. At my question there I have a quotation from Reformation Study Bible (2015) : > Divine illumination and persuasion is necessary for the heart blinded > by sin to respond to the **gospel**. From my question there, the conclusion : *"Lydia is not a believer in the sight of God when Paul walk to approach the women there"* because Lydia has not hear the Gospel yet (as Paul hasn't even sit there let alone talk to the women). > Genesis 6:9(NIV)
This is the account of Noah and his family. Noah > was a righteous man, blameless among the people of his time, and he > walked faithfully with God. > > Job 1:8 (NIV)
Then the LORD said to Satan, "Have you considered my > servant Job? There is no one on earth like him; he is blameless and > upright, a man who fears God and shuns evil." 1. When God declare in the verse above, are they a non-believer in the sight of God ?
2. what is the Good News heard by Noah and Job when they are a non-believer in the sight of God ? This question appear because in a Christian Forum (in our mother language) I propose that Cornelius (before he met the angel, before he met Peter let alone heard the Gospel from Peter) is a believer in the sight of God, but the Calvinist in that forum say that *Cornelius is not a believer in the sight of God before those events, although he worship God*. The same with Lydia. Their reason : *because they (Cornelius/Lydia) haven't heard the Good News yet... so, God hasn't regenerate them. Besides there is no text read that God already opened Cornelius heart before those events*. When I ask the two questions above, I get the answer which consistent with their reason ---> *Noah/Job are a non-believer in the sight of God although they worship God because they haven't heard the Good News, so God hasn't regenerate them yet.* That's why I ask here to confirm.