No he didn't commit suicide but I think everyone involved intimately with Inès b fore she was reincarnated remembers
People have memories through the following ways:
1. Suicide (given as punishment)
2. Wishes (for the next life due to the unfated death they suffered)
From the way Oscar said to Carcel that he made the smart choice, unlike Ines and Carcel, he must have used his wishes to gain memories so that he would have the advantage in the ‘second chance life’ to settle scores hinted by the way he took pleasure in taunting Carcel. Think of him like a lot of the regressed FLs in ropan manhwa who have memories and change outcomes to their advantage.
Does that mean in their first life Oscar committed suicide? Why does he remember his previous life?