Javik might still be in stasis on Eden Prime, given that it was apparently uninhabited aside from human colonists.
Depends on when and if he is found. I am doubting his stasis pod could last much longer. As for any of the species leaving behind something. I am sure the Asari and the Salarians would do so, I know for a fact that Liara would. As for my original question, I am going to stick with.............Once humanity reached a certain point of technology, I am sure the Reapers would return. And unlike this cycle, I am betting that the Reapers would have taken back full control of the citadel and made sure it stayed that way.
What made the current cycle unique was all the little details. Protheans uploading a virus to the Keepers and creating the conduit, humanity joining the galactic community ahead of schedule, Shepard and his/her crew. It was these little differences that made it posible for us to fight the Reapers in the first place. SO I am betting that even if we where not culled with this cycle, it would have made little difference and the cycle would continue with our eradication, with the newest Reaper being the Asari.