Do you think substituting any sort of nut (ie pecans, walnuts) for the hazelnuts would be good? Same with the dried fruit?

Looks like the author of the recipe anticipated this question. In the headnotes it says, "mix ins can be altered to suit whatever you have on hand, though below is my favorite combo." So, mix and match to your heart's desire! :)

Of course you can sub any nut and/or dried fruit you like for the ones suggested by the author of the recipe. Bear in mind, though, that when you do that you substantially change the recipe.

Absolutely! I like Pegeen's suggestions, but you could use almost any nuts and fruits. Your substitutions might be even better than the original.

Pecans or walnuts would be fine substitutes. For the dried fruit, I would use something like dried cranberries or dried apricot.