Hm. I don't use dry yeast, so I can't speak to that, but adding the butter after giving the yeast a chance to get going is important, imo. The softened vs melted butter business is also very important (again, imo.)

For the second knead, I'm talking about a short knead, where you go at it relatively gently for 5 minutes, with the first knead not being a super-extended affair either. The other way to do it, as you say, is to knead it only once, for a good ten minutes at the beginning. I have no scientific reasoning; my grandmother always let it rise twice, so I do too, and it always turns out just how I like it (imagine that!)