We were there last October with multiple life-threatening food allergies and they were FANTASTIC!! We spoke with chefs ahead of time and they also told us to stay away from quick service locations and use table service exclusively -- which we did. We ate at Makahiki twice (breakfast and dinner) and 'AMA'AMA six times. We also had shave ice every day, but you'll want to be careful as they use condensed milk at that location - so you would want to speak with the staff there and make your own safety assessment. (I have a dairy intolerance, so I wasn't overly concerned about cross contact, but they did review how they manage dairy with me, anyway, upon mentioning allergies.)
I would avoid the grill if you can. They are cleaned daily, but how clean is a grill, really? If you use one, be sure to put down foil to prevent cross contact. We never used them, but I saw many other people using them.
Our only disappointment with regards to allergies at Aulani is that the Golden Malted gluten-free waffle mix they use for allergies has a label that reads ok for most top allergies, but upon further investigation when we got home, we found out it is made on
undeclared shared lines with milk, eggs, soy, wheat, potato, and sesame. (All their 'Golden Malted' waffle mixes are manufactured in a peanut and tree nut free facility, though.) The chefs didn't know any wiser, so they aren't to blame, but I was less than pleased because it could have caused a reaction. That's the problem with trying new foods on holidays and relying on labels alone - it's scary. I have notified Aulani of this, but I am fairly certain they are still using the mix as their 'allergy friendly' option.
I would be cautious of the sorbets, too, unless you're familiar with the brand(s). A chef gave me sorbet once but I gave it to my husband because I was leery of traces not declared on the label. (Ha, I should have been leery of the waffles, too... but I was starving at breakfast and it was literally the only option, besides fruit that was safe for me.)
Oh, and there are 'Snacks with Character' treats in the store that are rebranded Enjoy Life trail mix and cookies. We also found a huge abundance of allergy-friendly foods and treats in the natural foods store near Costco. We wish we found that store sooner, actually - definitely worthwhile to stock up on all your favourites from home to make your own meals and snacks in your room.
Otherwise, the chefs took fantastic care of us. There are allergy menus available at both restaurants, but they're merely suggestions and shouldn't be relied on for life-threatening allergies. Always ask to speak with a chef when you arrive; they will review the menu and what can be made safe -- or maybe they'll surprise you and make something amazing not on the menu. We had some great surprises (when we asked the chefs to surprise us, plus one we didn't even know about.) Desserts will be limited, but we had a chef at Makahiki make a beautiful fruit 'cake' with tropical fruits. It looked too pretty to eat.
I'd go back to Aulani and eat there every day in a heartbeat if we could afford it more often. We'll definitely go back!
PS - I'm allergic to peanuts, tree nuts, potato, wheat, and sorghum; with a dairy intolerance and vegan preference.