Naruto has greater Bijuu control then the 1st? BS. Every single Jinchuruki has control of their bijuu to a degree, Naruto loses control all the time and has to pretty much beg the Kyuubi for chakra. Most Jinchurukis can manifest the full power of their demon, Naruto can't even do half (and loses control nonetheless.)
over the kyuubi? yamato just sealed its leaking chakra in an already sealed jinchuuriku. the 1st is never said to have had control over the kyuubi or have tamed it. i think the only1 who has even been conflictedly hinted at being able to COMMAND the kyuubi was madara. and wasnt the first trying to stop the kyuubi with his mukotan? why wud he need to do that if he cud simply ORDER it?
What does being as old as Oro have to do with anything? And you tell me to use common sense. Oro left the village. He had already did said experiments before he left. Yamato was the only one to live. Therefore it was before the 4th died. And probably before the 4th even became Hokage. So Yamato would be alive. He would have been young since he's about Kakashi age but he would have also still had the powers.