Learning Stepping Techniques

But the stepping mastery isn't locked, it's just the technique isn't available to the character. So what I'm wondering is does that mean the very first stepping technique they learn have to be trained IC and then any tech they make at mastered can be purchased or can you just purchase all the stepping techniques?

No Senta, Tesla said the mastery has to be trained to be unlocked. The stepping mastery is never locked. Things such as shunpo and Sonido are just techniques governed by said mastery. The race guides for Mod Souls, Humans, and Bounts all state that these races can learn stepping techniques by first seeing one and mimicking it to create their own variant. Nothing said they have to wait until mastered for their initial stepping technique, they probably can't have any special effects save for aesthetic stuff like they turn into snow or sand when stepping, but that's probably it. Another example would be how hollows and shinigami auto gain their stepping technique at a certain rank which would mean they never had it before, but it wouldn't need to be purchased or have them waiting until mastered to gain their initial stepping technique. So my question is, seeing as this mastery isn't locked period, can this stepping technique be bought or not. Not the mastery, just the technique themselves. Would it not be the same as if you went and purchased a tier I rei tech or kidou?