Naruto Thread (Spoilers For Sure)

Neither Orochimaru nor, the 3rd knew about the fact that those in the Death God's belly can't be summoned as those souls are in the pure world. Kabuto's version of Edo Tensei is far more advanced than Orochimaru. For all we know Orochimaru could have succeeded in summoning the body, but never actually put the body to use, either that or it wasn't the 4th at all. Kabuto obviously tried to summon a bunch of people and figured out the restrictions on the technique.

As for the person using Rasengan it could be:
Naruto (probably)
Edo Tensei Kushina (maybe)
Obito or Rin (highly unlikely)
Konohamaru (maybe)

All the other people who could use Rasengan are either dead, sealed, or somewhere else.