Partial answer: I was surprised to find that you can right click on the sun and get a "Save Object" option. I tried it in Vue 5 Infinite and it saved a s a .vob. Opened a new scene, deleted the default sun and loaded the .vob. It worked, lighted the scene from the same position and orientation - but no sun symbol in the viewports!

Right-click on a camera doesn't offer to save. Of course, you can write down the position and rotation on any object (+ the camera focal length) and just enter those again later.