This solo instance was ridiculous. I took on the quest at 26. I couldn't burn the adds then get to the Rurukuta fast enough to avoid failure. The Chuchuto just dies too quickly. After three or so frustrating tries, I decided to focus on Rurukuta instead, keeping up Featherfoot and running around to evade as much as possible. It took me a minute to realize that Chuchuto heals indefinitely..

I'm not sure if it's broken or if that's how it was supposed to go. Anyway that's what helped me through it. Hope it helps anyone thats going through the same thing.