Dragon Master on this page has, right now at 12:38 am pacific time, registrations.
https://www.rundisney.com/events/di...rities/disney-princess-half-marathon-weekend/
You do have to fundraise, or just pay a ton more for a bib than most want to pay, but I don't know what your friends network is like or how much you want to be there.
The first 3 charities are sold out, and it's possible the rest are, too. It's possible the one I mentioned will be by the time you see it as well. But it's worth checking out, if you wish to.
Going through the links...Kesem seems to have a few spots right now, but bigger fundraising requirements.
Share Our Strength might have slots.
Maybe Sophie and Madigan's Playground.
St Jude doesn't say "sold out" and let me click through to register for an account on *their* site to prep for registering for a race with them, so...
Anyway, like I said, there are big fundraising requirements so it's not for everyone (it wouldn't be for me!), but in case you hadn't seen that option...