Galatea was TRAINED by cadmus. This was how she was able to match supergirl and it was specifically mentioned by Galatea.
Skill are not imparted by their mindlink. Supergirl dreamed of Galatea training, but supergirl did not get any of galatea's combat skill.
If you say that clone RAnma has no mindlink to real RAnma, then how would clone ranma even know of Ranma's life? You said that clone Ranma wants to save real Ranma from the abuse, but there is no way clone Ranma would know of the abuse. Much of the happenings on in the household are private affairs that no one outside is witness to. That would be like trying to get a complete stranger to "rescue" Ranma from Akane by managing to deduce his entire life from just seeing Ranma and Akanae in school.
Ranma being cloned by cadmus means that they got a fresh meat body... but no Genma, no Happosai, no Cologne, no weird life, no special techniques and exposure to unique sources, no curse. Even if cadmus hired the top martial artists of the world to train the Ranma clone, it wouldn''t have the 10+ years of fighting experience that the actual Ranma has. Galatea matched supergirl because galatea did nothing but train in her short life but supergirl was sort of a slacker (At least to green lantern's eyes). Real Ranma practically lives to train. I find it hard to believe that clone Ranma will even make a dent against the entire of NWC then almost beat Ranma,
And why clone a normal 16 year old? "fascinates them" won't cut it. Likely, they'll clone saffron instead and then train him, rather than work with Ranma.
The third scneario makes the smallest sense. You keep stressing that Ranma has no super human powers... but he can analyze matter, superhuman abilities, plus energy maniuplation.