Osiris is definitely still alive. He is in contact with both Eris and the Queen on the threat of Oryx's coming. Toland's fate is a bit trickier, as we don't know whether he succumbed to the Deathsinger's Liturgy or not. But I believe I have proof that he is still alive and kicking: https://www.bungie.net/en/Forum/Post/150468655/0/0