I think I got it confused with the crap Nagato used to revive everyone. Edo Tensei can bring anyone back as long as they have the dna of the person they wish to revive.
Yes, but the original plan was for Tobi(don't want to spoil anything) to revive Madara using the Rinne Rebirth, Kabuto interfered with the plan by finding Madara's body and using Edo Tensei to revive him.
I'm thinking that the time limit was more a limit on Nagato's part rather than the Rinnegan. I'd be willing to bet that the Rikudou Sennin or someone fueled by the Juubi could resurrect anyone no matter how long they've been dead.
Rainbow Dash is best pony. The only argument I will accept is for Twilight Sparkle.
There's no known time limit on rinne rebirth stated. It wouldn't make sense considering they were going to use Nagato to use rinne rebirth and bring back Madara.
Honestly this whole rinne rebirth thing is bad writing since you could ask:
1. Why didn't they just bring back Madara earlier before the countries were allied?
2. In Edo Tensei you're brought back with all your jutsu intact so why couldn't Edo Nagato use rinne rebirth? If he could then you'd have an exploitable endless cycle of rebirth since people brought back with edo tensei are immortal and the rinne rebirth requires the user to die after using it.
3. If Obito is a villain because of the sole fact that Rin died why didn't he bring her back through rinne rebirth or edo tensei?
4. If Jiraiya couldn't be brought back with edo tensei because he was at the bottom of the ocean, why couldn't he be brought back with rinne rebirth?