Woohoo theories!
beaches / clanger I don't think Pratt was involved in the abuse ring - his estranged wife said he'd seen something appalling in the town, presumably the abuse, and that's why he sold in a hurry to Bunny, to get out. She offered twice as much as Matt was gong to pay. Maybe Bob had taken the pictures as evidence, to cover himself? Or seen the pictures onlin and recognised the kids?
alpine presumably the DNA testing was a criminal matter, to determine Tui's rapist. Though it does seem pretty casual for the police chief to just turn up with results. I think the results could have been forged or not.....remember the pathologist saying that there was no trace of semen in April's vagina, implying the gang was careful. And surely Campion wants us to believe that Matt really isn't Jonno's father, so he and Robin can have their happy ending?
I wondered whether Matt was abusing Tui separately from the ring...the scene with the sons accusing him was interesting, and his bizarre reaction to Tui's disppearal - first total indifference, then determined to get her back, almost like a lover. But then he was so weird about his mother, why not his daughter. I think Matt's drug operation was to make the money to buy Paradise, I don't know if he knew about the abuse ring. The money / drugs passing between him and Al could have been for Al to look the other way on the drug operation. In a weird way, I think Matt had some bizarre moral code. His reaction to Jamie's mother seemed like genuine dismay, and his reaction to his son's accusations true outrage. impressed I think you're right, that Robin's theory about 'no one' was right.... And I think that it was when she shared that with Al that he targeted her. I think he roofied her (not sure if he raped her, in a weird way I think he wanted her properly, and his marriage proposal was genuine) then accused her of embarrassing herself to throw her off the scent, make her unsure of herself.
But I really like the ambiguity we're left with. To me, Campion makes the entire community complicit. Even Jonno in Robin's rape.
Favourite moments: Robin stabbing Sarge, Tui shooting Matt and Jonno (the shooting of Jonno I think was interesting, he was ostensibly innocent but Campion makes no apology for it in later scenes), Robin shooting Al. Yeah! I loved that the women got their own revenge, and bloodied their hands.
The only thing I didn't like, was the scene with Bunny's daughter playing guitar in the last episode. It just jarred with the nuance of the storyline I thought.
Sorry, essay! 
I am going to watch it all again! I think the way Campion builds it all up is masterful.