The outcome (and progress) for the whole chain can be overheard. The matchmaker is gossiping about it as you walk through Val Royeaux. No matter how you resolve the chain, there will be something to witness in one of the large open areas on one of the upper tiers, and you can interact with them in at least 2 of the outcomes. I usually have the couple elope so I can tell the matchmaker to mind her own business, or at least that's my mental interpretation of the interaction. I tried most of the permutations of the chain, and there is at least one outcome that I didn't follow up on, because I didn't read all the text and wound up doing the opposite of what I wanted. I don't think there is any difference in actual reward, other than a very trifling influence advantage to doing it one way rather than the other. It's just the tone of gossip that changes in the capital. Maybe in DA4 there might be a different wartable op or codex entry, but most likely it's just something interesting to do in Val Royeaux.