1) Yes, in the current release, only the buttons 0,1 and 2 are used as they jump to to far away points. We did not really have a use for the keys 3 to 9, as all other parts are reached quickly from these main central points.
2) Yes, the photo mode is a whole complex animal on its own with not to well documented controls. It’s more like a “bonus feature” in the current version. When in “Advanced Mode” you can create very interesting photos. The keys W,A,S,D move the camera around horizontally and Q and E move the camera up/down. Mouse is for the rotation and “SPACE” saves the current view as a screenshot. The shots are saved in BEAMFORGE_V2/saved/screenshots. Using “image scale” you can take photos that have a bigger resolution than your screen-res. I.e., if your screen is set to 1920×1080 and you image scale is set to “2”, your shots will be saved in 3840×2160 etc. Making shots look really crisp in high resolutions.
3) Not really. If you zoom-in and hold, it will zoom in for as long as you hold it. Releasing the button zooms back to your original position. If you want more control about taking pictures, you should use the camera mode, as that allows you to completely freely zoom and move around the environment.