Thanks for sharing... I can see how your personal experiences allowed you to connect with this film in a way that I could not.
Yes, the emphasis is on visualization of emotion --- facial expressions and particularly the depth of emotion conveyed through the eyes. Enzo Staiola, the boy who plays Bruno, may have been selected specifically for his eyes according to an anecdote shared by the actor (see video link below) and one of the most important scenes in the film captures his gaze as he watches his father ride by on the bike he has resorted to stealing. Another important feature of Italian films generally of the period, not just those of the neorealists, is the dubbing of other actors' voices onto the audio track, an artificiality that lays a heavier burden on the visual to convey the requisite emotion.
I'm glad that watching this film has been so beneficial to you.
The idea of children as the future is a common one, proffered both in cinema and in general discourses circulating in society, but if I might suggest an alternative way in which the neorealist filmmakers (also) conceptualized the child in their films. Antonio's desire to provide for his family and willingness to work is admirable and one can and should empathize with his plight, but he is also a flawed character who neglects his parental duties --- indeed, there is a reversal of roles in the film between father and son. The viewer is introduced to Bruno in the home polishing the bike and tending to his infant sibling, he opens the window to let the light in, an action highly infused with symbolism of his role throughout the duration of the movie. He is dressed for work and, prior to his father securing the poster job, has been the one providing for the family with his job at the petrol station. The boy symbolizes the working-class Italian people and their resiliency --- he is constantly being bumped or hit by adults, tripping and getting up. He is also imbued with innocence, as children are generally in cinema, which positions him opposite two guilty adult parties associated with fascism. Much more could be said about Bruno and other kids who feature in the film in minor roles, but I need to hold back a few gems for the book...
Ah yes, the young man who steals Antonio's bike early on in the film... it is not clear whether the seizure he suffers when caught and facing charges is real or staged to illicit sympathy and evade arrest. His mother comes out onto the street and holds him pietà style, one of several religious cues in the film. There is a subtle prop associated with this unrepentant thief --- his hat, which is a German army cap and which aligns him with the Nazis who had occupied the country following Mussolini's downfall. As you note, he is the first thief... the second is Antonio himself, who is symbolically aligned with the Italian fascists --- he is patriarchal, ordering Bruno about, he slaps him at one point, there is no physical affection expressed for his son, he is absorbed in his pursuit of the bike and neglects the boy who is nearly run over by cars on a couple of occasions, and even the trip to the restaurant is far from altruistic as it is functionally a bribe so Bruno will not tell his mother about the slap as he has threatened to. My intent is not to paint Antonio as evil, but realistically as a flawed man in need of redemption.
Films -- at least the good ones -- function on multiple levels and Bicycle Thieves
is rich in this regard. I hope you were able to watch it a third time with the idea of Christian allegory in mind re: my brief off-thread comment. I've dropped a number of hints in this thread about it and I look forward to your further comments...