I don't think Dani and jack are set up, I don't think they are good enough actors, I think they put people in there who they think will be attracted to one another and sometimes it works, sometimes it won't. For example, I would assume they thought Alex and Laura would get together. I don't think they'd have assumed Laura would jump on wes as soon as she saw him. No one would have predicted that.
All these dramatic events get people way more air time, like Megan, wes, Adam, Rosie etc. Frankie was quite late to the party, and people already loved jack, but past that he's quite funny, they won't show Frankie for the sake of it if nothing interesting is happening. They will just pick the best bits and what they think will keep our interest.
And it's not scripted, directed maybe, but not scripted. Directed as in sit there and chat to x about y. But they don't tell them what to say or decide who has already won. I doubt they give a shit who wins. They just want ratings.