c. View Navigation
This option physically moves the camera using the VFB instead of the view port. Unlike real zoom, this really is changing where your camera is placed in the scene. Turning this tool off does not return the camera to its original location; however, clicking in the viewport will allow you to use undo (CTRL + Z) up to the max undo levels (default of 20) you have set.
Manually restarts the render, but takes in account for certain changes that wouldn’t normally affect IPR. For example, if displacement values are changed, they will not update automatically; the render needs to be reinitialized for certain changes like displacement, render settings, etc.
e. Select Object
Pretty self explanatory. When this option is active, it allows you to LMB on objects in the render to make selecting easier in busy scenes. I personally don’t use this very often.
f. Get Object Material
When active, this option allows you to LMB to select materials in the VFB which will then open in the material editor. If the material editor isn’t open, it will open it for you. Also, it will create a new tab view to keep your selections separate from your current working space. See GIF below: