You don't want the answers to these questions... This post is satisfying your curiousity... Move along...
But, seriously, there was one other continuity error that I thought of. It was pretty clear in ep 5 that Obi Wan didn't know that Luke had a twin (OW: "That boy is our last hope" Yoda: "No, there is another."), yet in ep. 3, he's in on the whole birth.
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I was under the impression they both knew, but it was merely soliloquy for the viewer's benefit.
That and what Nurbs said.