I like to personally imagine that the Bearer lives up to the nickname the Gods gave them (I also like to think that many different being have their own 'terms of endearment' when they refer to the Essence's split form) and instinctively absorb any loose source fragments for later use.
Not too sure (I ended up experiencing it too when I just tried the game out once more). Maybe change some of the choices you made in the beginning?
If he really is the dove of the Prophecy, I really hope that when the time comes, The Bearer can potentially give the Sisters of Fate a shock of their long life and does a action that may affect Saint's own survival as well.
Though it'd be ironically funny if the Essence, despite being part of the prophecy itself, has the strongest potential of messing with the fates in ways that the Gods couldn't see coming. Like The Bearer at one point meets the Sisters and they show them the Wheel and the multiple threads of Fate on it. But when the Bearer asks about their own thread, they drop the bomb by saying something like "The Essence is unbound from our Wheel".
Onto my randomness I guess
You know, I feel a little slow for just realizing this about Adonis now, but the reason he is one of the people who is willing to give the Bearer a chance may be because of his own experiences with rumors. He's probably heard all the kinds of things that people have whispered about him (or stated right to his face) and knows firsthand that out-of-hand they can get and what a poor picture they can paint of a person. So as long as the Bearer makes the effort to be friendly, he's willing search for the real truth of the matter. And Cally's own experience with her first meeting with Aeson may likely be a strong core to why she is willing to offer just as much friendliness; because she sees a number of similarities with Aeson and the Bearer's situation and initial reception when it comes to Olympus.
Saint's fierce loyalty to his friends and relative thoughtlessness toward others is likely why he not only seems to have the slowest trust growth of the others, but is also the quickest to throw accusations at the Bearer and voice doubts about the Bearer.