Re: 510 - 3. On the street.
I think that scene - which is one of my favourite of all the five seasons - shows that they're still in love and hurting for being apart, but it also seems to me that there's a sense of finality in it.
I see Justin first amused and then resigned that Brian isn't going, rather than disappointed. They believe they are worlds (continents) apart, at this point: Brian going to Mardi Gras and Justin staying to fight "the good fight". I don't see any sign that would lead to a reconciliation without the bombing. Except, of course, that they love and miss each other: but that has always been true.