Talk to Archie each night at the bar and when you see him in the nightmare on landings. He's usually with Todd at the bar. He has longer hair and a red tie. He will be there on:
Day 2 from opening to 21:45. Start the path for him and Todd at the same time. Answer: "Maybe..."
Day 3 from 21:35 to 22:15. It's later in the night (over halfway), and they aren't there for long, so make sure you talk to them when they are! A: "Lots of money."
Day 4 from 21:10 to 22:00. He's by himself today, in the lower-left booth (where Morgan sits). Once Daniel leaves, he's next, so catch him when you can! A: "Of course" to both questions.
Day 5 from opening to 21:15. By himself again. He should be the first person you talk to, because he leaves quickly. No question.
Day 8 from 21:50 'til closing time. You can't miss this one, as you are allowed to linger as long as you desire.
You also need to talk to him each time you see him on the landing during the nightmares. He is the "Long-Haired Sheep". Just be encouraging here; the answers should be obvious. But let me know if there's one you aren't sure about.
NOTE: I am 99% certain I gave a "wrong" answer or two at the Stray Sheep, according to the wiki, and still popped all the helper achievements. I include the answers so that you can be on the safe side, but you may very well be able to answer however you like. If you have confirmation of this, please comment. If you want to be safe, answer as posted above.