You are more or less spot on as far as the technology is concerned, although it does differ slight from place to place. Gondor, for example, has plate for most of it's soldiers while Rohan tends to use more chainmail and leather. Different cultures also have different cultural inspirations from our own world, such as Rohan being molded largely of the Anglo-Saxons and Vikings.
There are different races of humans and depending on what race of human you are, you will live longer. What determines how long you live is how closely you are related to the men of Númenor, who founded Gondor and Arnor. So, if you are from Rohan, you might live to be into your 60s or 70s if you are lucky, since they are descended mostly from men of the north. But if you were a Ranger of Ithilien, you could live well over a hundred.
I believe that Bilbo does have a clock, but since the earliest mechanical clocks were mentioned in our world around the 12th century, I don't think that is too much of a stretch.
As to prophecy, I'd say it is a rare gift and that their are different kinds. Boromir and Faramir both have prophetic dreams about the Ring, while Elrond has actual foresight, although I suspect that he sees many alternate possible futures, otherwise I imagine he would have been much more positive about the Fellowships chances.