I actually sell this type of equipment for a living. Harley rakes are generally used for leveling and rock removal pre-sod installation. Final grade work can also be done with box blade on a small compact tractor. The track loader/Harley rake is a very aggressive approach. If you are wanting to re-grade your entire yard, this is the fastest way to do this. you will aslo have issues with soil compaction and access due to the size and weight. If this option is hard to find, There are also 3 pt mounted Harley rakes for small tractors or a mini dingo with Harley rake attachment. Looking at all of your pictures, If it was me, I would rent a powered dethatcher first and hit the high spots hard, then I would hit the low spots with an 80/20 topsoil/sand mix. I always hate to see all your hardwork get torn up for no reason.