Gosh.... it's been so long since I have thought about this movie. I have notes for everything except extract 5 because at OHS we didn't bother with it, as it was in the HSC the year before (2003), so... I'll just look at the script and think of something.
Your question seems very vague - What I would say about the theme Tolerance of Difference on the whole film? Or in the end? As I think the biggest theme is Coping with Change. Marius goes on his whole story about how he lost his wife and kids - and the fact that he hadn't drunk until then is a BIIIG thing in the story, as he made a big deal out of never drinking.
The way he coped with changed was not very well, as in Ex 5:
Marius: C'est a` cause des petits que je suis pas revenu. Hé, il faut du courage pour aimer les enfants, et ce courage, je l'ai plus. Alors le matin je les regardais prendre le petit déjeuner en famillle.. c'est ça, la famille.
He had no capacity to love a family again, as he had lost his, and that killed his spirits. So this is what pushes him back to drink, and that causes him not to go back to Jeannette and the kids(remember a bit back - he left and didn't come back for a while,all got really 'oh no he left'.).
As for T of D.... that's a stickler. Perhaps.. I have no idea! Perhaps it is the fact that Justin and Dédé have to adjust to the fact that Marius now comes with the baggage, as before he was a very insular silent person, now he has a soul. But that could mean nothing.