If my assumption is true, all chars should learn the spell when you talk to the god inside the cave and when you are teleported back to your group, the others should mention that something has happened to them (= learned bless spell too).
You are right - when you talk to god all your party members learn the spell (they didn't used to).
The one that talks to god gets blessed (for 3 rounds or whatever it is) as well as learning the spell.
I can't remember in the dialogue if they are talking about learning bless or being blessed though. I'll check it next time.
