Watch the Video on this FAQ: Traveling after applying for naturalization/citizenship pending
1. That's not a problem.
3. As long as you appear for biometrics or request that biometrics has been scheduled, I don't see any problem.
4. I don't think that matters either.
5. No, it is not needed, as long as your taxes are paid up I don't see any problem.
6. I don't think three weeks absence is going to cause a problem in the domicile requirement. But if you want to be overly cautious, you can come back and stay extra three weeks before you apply.
Note: This is a verbatim transcript of the referenced audio/video media delivered as oral communication, and, therefore, may not conform to written grammatical or syntactical form.