1- Obito doesn't need Susano'o genius. While I compare him to Madara I meant about their capability to see, not the powers of their Mangekyo. Obito can see Mu even if he goes invisible therefor Mu can't sneak up on him.Correct. But when Mu is invisible, his chakra also becomes invisible, not just his physical body. That's why he wasn't able to be sensed by ordinary means by the sensor division. That's why Obito cannot see him when he's invisible.
I already know that. That's probably the reason why he has to become visible to use jinton genius. However, stabbing Obito with a blade doesn't require him to become visible and give away his position. Also, comparing EMS madara to the obito situation is stupid. Once Madara uses his complete susanoo(he used it in the manga against Mu and Ohnoki) the only way they have of breaking through his defences is by using Jinton-and that requires Mu to become visible and gives away his position. MS obito has no such technique.
Irrelevant.
2- Mu's chakra is not invisible. He uses chakra to make himself invisible. Sharingan can see chakra, any type, any element it does not matter against sharingan's capability to see them.
3- Obito can see the chakra build up if Mu tries Jinton and make precautions. Such as Flame formations or just going intangible altough jinton and kamui is restricted which changes nothing as Obito still can see Mu with Sharingan.
4-And about the picture, I think it fit there just well to make my point.