No need for the extra guide clips. The machine comes with one and it takes a ton of use to wear it out.
You also don't need the diamond plates. I think the shapton glass stones in the set are all you need but if you had some knives that needed a lot of work you could add a 320 glass stone to the set. The one accessory that would come in handy that is not part of the set is a flattener of some kind. Coarse 120 grit sand paper works and so do dmt plates like this one: http://www.chefknivestogo.com/dmt2x6diplfo1.html