You make a great point about Buddy, I really really really have no idea yet what to make of him. When Quinn meets with him, he asks "Have you seen her yet?" and then points to Quinns eye, the same symbol that her dad wore, so I assume he refers to Quinns mother ?! And then he goes on how he takes care of her, but we have no idea what that means, keep her high ?
Regarding Riona, I first figured her stalker would be related to Quinn getting whacked and robbed, either the wannabe maggot that stalked her was a distraction or she still is being stalked and then I'd assume its for the same reason as Quinn getting robbed, ruining their drug operation by trying to rob Riona too.