In The Fourth Shinobi World War Orochimaru gained Zetsus Body, which granted him his Wood Release (in my opinion all his Techniques) and his Body. What we know about Zetsu is he was one of the first victims of the infinitie Tsukoyomi and were pulled out by Black Zetsu after being cultivated with Hashis Cells. he doesnt has any organs but massive amount of Chakra. The fact that he lived so long in the Statue of the Outher Path makes him near-immortal and he cannot die by simply living but can be killed.
White Zetsu(and clones) is just a much weaker version of Hashi, which would give Orochimaru access to all of his abilities albeit on a much weaker scale. This I assume is also true for his healing powers, also Orochimaru's immortality jutsu only last for three years because the other consciousness begins to reject him. All Zetsus have a consciousness, so no I don't think Orochimaru is now immortal.
What do you mean with the " ..and Sharingan " part?
Orochimaru gained that near-immortallity from Zetsu, his plant like body and Hashis Cells made the body so strong that Orochimaru doesnt have to find another host, because it doesnt turn against him after 3 years. Orochimaru have a Shin Clone with two Mangekyou Sharingan in his Hideout, but dont want to take that Body, because he would lose his near-immortallity with Zetsus Body. He only wanted the Sharingan because the ability to copy abd learn fast all the jutsu. So Orochimaru choose Zetsus Body, because he has all the time of the world to learn all jutsu and turn against the Sharingan. What are your thoughts about my Theory and what are yours why Orochimaru dont take Shins Body?
I think Oro is still after Sasuke and/or his descendants, he even stated that after he was revived. He didn't take Shin's body because it's only a clone of someone who was not an Uchiha in the first place and probably would not have greater potential. Still think that zetsu's reject him after 3 years, interesting theory though.
It's explained that the Zetsu are what remains after Infinite Tsukuyome. I don't think having your chakra sucked out for decades and then turned into a half-plant clone makes you strong. Spiral Zetsu was strong because he used Yamato, which is why he was able to summon considerable abilities like the giant wood statue. However, most Zetsu have only fairly weak powers. Zetsu's strength was his ability to spy and dispose of bodies. Not his fighting prowess which the Zetsu simply did not have.
Orochimaru clearly has switched to a new body in Gaiden which is why i doubt Zetsu would give him immortality. As to why he doesn't use Sharingan, we don't know. But judging from how Shin worked out, i think he was actually working on turning Shin into an acceptable Uchiha substitute.
Well I'm not sure about Orochimaru being immortal but now that he has Hashirama's chakra through white zetsu all he really needs is the Sharingan and he would be kinda like Madara 2.0. That being said I can't see him wanting to become a jinchuriki nor does he really need to be. Firstly he fought Naruto on even footing even though Naruto was in tailed beast second state most of the fight. Secondly I don't think Orochimaru would be compatible with any of the tailed beasts (except MAYBE Shukaku). Also even if he got the Sharingan all that would do for him is allow him to copy any jutsu he saw. This would all but invalidate his reason for his experiments so I for one think that Orochimaru just wants to think he wants the Sharingan but he doesn't really.