Many set up around 5 but don't 'open' until 6, though I'm sure they wouldn't turn away cash.

No, it's still helpful. Although that was my guess, it's up to them/5 am at the earliest. Thanks!

Every street vendor has their own times. Halal ones open as early as 5am just in time for dawn prayer. I usually see non halal opening up two hours later.

Edit= realized this was 4 hours ago so you probably don't need info anymore.

So it's 2:30 am, I just woke up, have no windows, and would like to buy breakfast from the guy on the corner without going for many unsuccessful trips down the cold street. Anyone know when the guys that sell coffee, egg sandwiches, donuts, etc generally show up?

When do street vendors generally open?