I'm not trying to "spin" anything. We just agree on the same fundamental point, but the way we extrapolate it differs. I already said that fighting game characters can be unique, but that uniqueness is limited. As an extreme example, you won't get Hero's menu mechanic from a fighting game character.
By your logic, if a Tekken character like Heihachi were to get into Smash, they would share the same general play-style and mechanics of Ryu, Ken, and Terry: auto-facing, complex directional inputs, different move properties depending on how long the button is held, and projectiles.
Of those four, Heihachi would only share the auto-facing mechanic. The others? Nowhere to be found in Tekken, a series where there's little to no projectiles, you chain button presses and simple tilts instead of directional inputs, and moves are sorted by height instead of power (instead of "Light/Medium/Heavy" punches and kicks, you have high punches, low kicks, etc.) Did I also mention that the aerial game in Tekken is almost nonexistent?