Since you brought up that 18's stance and martial arts skills are based on what she learned from Krillin, does that tangentially make her a member of the Turtle School?
Well, yes and no. Master Roshi's description of the Turtle School is rather similar to that of Bruce Lee's Jeet Kune Do, in that it's not a style in and of itself, but a collection of them. It borrows from what works in every style and teaches the practitioner to find what best works for them.
Having learned from Krillin though, she would presumably also have been the recipient of some of those teachings as well. So in a sense, yes.












