dont know about this one.. prob not. cause its just speculation.
but obito did slay uchia. but under the prenote of being madara.
not because of some grudge torwards them.
i think obito would rather be Jinchuriki than. sauske.
obito was just gonna use him. id say we woulda seen some talk from obito/tobi. that would give us more thought on that.
but looking back. there is none. so really i dont know how. but you must of came up with these ideas. from other speculating. or somehow. you really are derped ; ).