Like colmc says the preclearance times can be quite variable. If you don't have a US passport or Global Entry then even a short line can vary depending on who is in the line ahead of you.
That said, I've never actually been stuck waiting more than 10-20 minutes. I would be pretty comfortable leaving the lounge 45 minutes before the flight. An hour is more than enough.
After preclearance there are very few services. There's a coffee stand that sells a few things and some vending machines and that's about it.