Kakashi can't use Amaterasu, Susano'o or Tsukuyomi because his Sharingan is not only different from Itachi's but because he doesn't have TWO Sharingan. Susano'o and Amaterasu are in one eye each, I think it was the left eye contains Susano'o and the right contains Amaterasu. In any case, Kakashi's only able to use Kamui because that is his Mangekyou Sharingan's ability. The Sharingan abilities do differ but in order for one to use these abilities they must also be of the Uchiha clan, I believe. Danzo was an experiment of Orochimaru's, Tobi does not have Obito's Sharingan. Stop mentioning Obito, he died back in the Kakashi Gaiden chronicles with half his body crushed. Tobi's ability to become intangible is part of his sharingan, it's unique to him. The Mangekyou Sharingan has different abilities than others. It's unique to its user. Hence why Itachi can't use Kamui. Obito being a dead kid is being constantly brought up as secretly being Tobi, or Tobi having Obito's Sharingan, Even if one could remove the rocks from Obito's body, half his face would be crushed beyond recognition, The eye would also be crushed. Izanagi is a forbidden Uchiha jutsu that Danzo used. Izanagi is NOT a technique that can simply be mastered, as seen during the Sasuke vs Danzo battle, every time Danzo used Izanagi, one of the Sharingans in his arm would close. So no, Tobi has NOT Mastered Izanagi on a totally different level. If Tobi were to use Izanagi his eye would've closed over permanently. As for how Tobi warps his body without using the MS, it's currently unknown, However, As shown in the battle between Tobi and Minato, Tobi cannot attack while intangible. He has to become tangible in order to attack. It required the flying thunder god technique for Minato to hit Tobi with the Rasengan.