A few questions there ozzo.
The bit of oil sounds like it's sweating rather than leaking, it's covered in the handbook and is not a problem.
Different people have reported different running in experiences, from perfect straight away to starting to get better at 1,000 km. Mine was noticeably quieter from 400 miles and carried on improving till about 2,000 miles. Depends on what your few hundred miles are, I wouldn't worry about it till you're past the 1,000 mark.
I doubt changing the oil early will have much affect, I changed mine early but not till after the running in period. On the other hand it wouldn't do any harm, except to your pocket. That's the advantage of buying oil in the 1 ltr size, it's enough to last a lifetime and once you've bought it you may as well use it.
Rohloff recommend a new drain screw and seal when you change the oil, I can't see why unless the seal is damaged. I've changed the oil twice with the same screw and seal. If there's a problem it'll leak and you'll see it.
