Need to know the connections (Possible spoilers)

I wish I could help, but I'd like to know the answers to these questions myself.

1. Hick's lived in the same place as Quest. Somehow, Hicks found out what Quest was up to--perhaps Quest let it slip while under the influence--and he stole the film, so that he could cash in.

2. Orrin is definitely the ice-pick killer. Alone in the big city, he acquired a number of "bad habits"--including drugs, supplied by Dr Lagardie, and skill with an ice-pick. In the novel, he had begun studying medicine in college, providing him with basic knowledge of anatomy which helped him use an ice-pick effectively.

3. Hicks had the claim ticket for the photos, and was killed when he refused to give it up--apparently by Quest.

4. Dr. Lagardie was the dope connection for Quest and others at the place where Quest had lived. When Quest began to initiate the blackmail scheme, he must have felt that he should relocate to avoid any repercussions, so he went to Lagardie--perhaps offering to cut him in on the deal.

5. It's more clear in the novel, but, yes, Lagardie, who had been dumped by Dolores and had never gotten over her, killed her out of jealousy, altho not due to Marlowe, particularly.