Okay, now I understand your question. From the manga, there are no details on how Kakashi actually got his MS. If you read the wiki on him, it basically says that "he got it through unknown means". It seems most likely he gained it through means of prolonged grief over lost friends/ family. I doubt he actually killed a friend to get it, which is why I said "extreme distress" or even just extreme emotion. Its not a requirement to kill your best friend, that's just a good way to trigger such emotion.
I have no idea why his MS power is space/time either, but that's why I focus on the powers spawned as being 100% unique, and maybe completely random. Plus since Kakashi has only 1 sharingan, it makes sense that he has only one MS ability. Unlike a true uchiha that could have 3 MS powers (one right eye, one left eye and one using both eyes). For this reason, I still think that Madara has 6 MS abilities, 3 from his MS and 3 that he gained from his brother's MS by taking his eyes and gaining EMS. These 6 might actually be the 6 path's powers (sound possible?). He did say that the rinnegan used to be his.....
The Byakugan has always been back burner topic, but I think the main long term importance of that eye is that the Sharingan developed from it (if I remember that right).