My wife set an about 6" diameter burning hot pan on the countertop and created a burn spot about 1/2-3/4" across, and another bubbled up area that when opened and sanded will be about the same. Any recommendations for fixing up these spots?

I'm putting a high shelf on the wall in my garage. The brackets are heavy duty, 20" deep and bolted into the studs. There are 3 brackets, 32" apart, and the shelf will be 72" long. This shelf won't hold a large amount of weight, but I don't want it to sag either. I ruled out melamine because it would probably sag under it's own weight due to the 32" span. I could use two 2x12s, or 3/4" plywood, or a nominal 1" (actual 3/4") edge-glued pine panel I already have. I think if I used the 3/4 ply or pine panel, I would want to add a 1x2 (actual 3/4 x 1-1/2) edge strip to avoid an possibility of sagging. Seems like the 2x12s are the easiest, and I have another shelf like that on the other side of the garage with an even wider span. I could just have the lumber place cut a 12 foot 2x12 in half and I'm done. The other options would require the extra work of attaching the edge strip (probably both front and back). In the case of the edge-glued panel, I'd be concerned about the boards in the panel separating under the stress of attaching to the brackets, as this kind of panel isn't really made to be used as a shelf. Unfortunately some of the screw holes in the brackets seem to fall in line with the seams in the panel. Pros and Cons, opinions? Rants and raves?