If I put a picture on my Mac to photostream and it moves to my iPhone's photostream and I delete the picture from my photostream on my Mac, will there still be a picture left on the iPhone in the camera roll?
When you delete an image from Photo Stream, there is a message (at least on iOS) that says something like
The image will disappear from Photo Stream on all your devices.
Hence, deleted means no longer in Photo Stream anywhere.
Yes. the photo remains on the camera roll, but deleted from the stream.