On the topic earlier of Echo vs. semi-clone, it's not an either or situation, cloning exists on a spectrum. Additionally, from what we seen Echoes aren't just clones, they're essentially glorified alts, with practically 1:1 body structure and few actual gameplay differences; Lucina is negligibly shorter with negligibly shorter reach (a matter of a couple pixels, so practically irrelevant) with the exact same movement specs/physics while all her moves function the same with the same frame data as Marth's (just with consistent strength throughout and no tipper), and then Dark Pit is the exact same in everything except for his f-tilt having weaker knockback, his jab finisher having a smaller hitbox (this one probably an oversight after a patch made Pit's bigger without doing the same for Dark Pit), altered arrows (stronger with less control), an altered side-b (stronger with horizontal knockback), and a different final smash. Even the Melee clones were substantially more different than this (as they had different shapes/sizes, different movement specs/physics, different frame data and damage/knockback values on pretty much all attacks, many moves having altered functioning, and even a unique move here and there). Dr. Mario avoids the Echo designation for this reason, while calling him a semi-clone is still not accurate from what we seen. The general cloning categories goes like this:
*Echo Fighters (as covered prior)
*Clones (most if not all moves cloned from another character, but most if not all aspects have been altered substantially so that they are legitimately distinct in how they play; the six Melee clones and 64 Luigi are examples).
*Semi-clones (has a significant portion of their design/moveset cloned from another character, but has just as much or more that is unique to them or drastically altered that labelling them just a clone is misleading; 64 Jigglypuff, post-64 Luigi, post-Melee Falco and Ganondorf, Toon Link, and Lucas are examples).
*No real accepted term for this; characters with a few cloned aspects but mostly unique (Wolf, post-64 Jigglypuff, 64 Captain Falcon and Ness are examples).
Then additionally the individually categories themselves are on a spectrum; for example among the Melee clones Ganondorf is significantly more different from his source character than Dr. Mario is, and among semi-clones Lucas for example is close to the semi-clone label being questionable while Brawl Toon Link is on the opposite end of the semi-clone spectrum.