Since the potatoes are no more authentic than the noodles (and adding pineapple and red pepper is a lame attempt at trying to authenticate the dish), I'll go with the potatoes.
Ohana is supposed to be a restaurant with south-pacific inspired cuisine. Neither lo mein or potatoes fit the bill, so this whole "it's more authentic" arguement is lacking because neither are authentic.
And I'm of the opinion that the new "additions" would have been better suited at a restaurant like Lotus Blossom Cafe.
I could find the noodles (the new wontons, too, for that matter) at any Chinese restaurant. And I'm from Chicago and we have Chinese restaurants (as well as every other cuisine possible) seemingly everywhere, and I can't think of one place that DOESNT sell pork-filled wontons or lo-mein.
Take away the potatoes, fine...but at least TRY to authenticate the menu. If you're only going to replace one non-authentic item with another, at least make it tastier, or something not so commonplace.