- Mū is completely hiding his presence, including his body, so there wouldn't be any distortion. It sounds like you're referring to the jutsu that Taiseki used, which is inferior and can be seen at a close enough distance around his body. Like I said, Minato hasn't showed any hightened senses, so trying to locate Mū that way would be futile for him.
- Ok, but it'd be harder to avoid someone who you can't sense, see, or smell coming up from behind you and stabbing you. Specifically someone who is fast and has great reactions and reflexes
- Fission is a technique on a completely different level compared to cloning. He might sense the presense of another Mu the second he splits, but they'd immediately go invisible and change location. I already said why I think bunshins are rather useless here