Some objects from top, bottom, left and right views will just disappear, especially if they're lined up right on the grid.
You're better off using Perspective (it doesn't have any affect on the Active camera view which is what gets rendered.) In perspective view, you can rotate the scene to very close to top, bottom, etc. (with the "Orbit Camera" control [middle 3D View Tool icon top right of the canvas]) ... but with enough of an angle to be able to determine where your objects are. (Also, before moving around in perspective view -- select a group or object that you want to focus on -- if you select a camera or light you'll "go wide" of your view...) [Double clicking on any of the 3D View Tool controls will reset the scene.]