Hi Mary Ann!
Thank you for bringing your question to the Disney Parks Moms Panel!
While the course is still being finalized for Star Wars Half Marathon -The Dark Side, I can tell you what runDisney generally offers for their races and will probably offer for the Dark Side Challenge.
The drink stops for the 10K will have water, and there should be at least three along the course. The half marathon will offer about nine drink stops with both water and Powerade at each stop. From what I have researched, Powerade seems to be gluten free, but you will want to double check that.
Around mile 8.5 of a half marathon, Clif Bar (an official partner of runDisney) products will be handed out. They are usually the energy gels in a variety of flavors. You can filter Clif Bar products for "gluten-free" on their website. (
http://www.clifbar.com/find-your-favorite)
I would encourage you to bring your own gel/chew to be safe. I am not a fan of the energy gels anyway, so I usually pack my own in my race belt. I actually like to have something salty, so I pack a Ziploc of pretzels. There will be a huge selection of gels, chews, bars and more at the race expo when you go to pick up your packet, so you could always do some shopping once you're there.
I hope this helps! Please let me know if you have any other questions.