Re: Feeding water
You can refer to the sites below for reference
kellymom.com :: Guidelines for offering water to breastfed babies
Re: Blocked nose
Same case for my boy. The problem is more prominent when he sleeps in an air con room. It's normal for NB because their nasal passages are short and they're adapting to breathing outside air. Try to clean his room more frequently to remove dust.
That time he was using Otrivin for 3 days, stop for 1 day, then can continue to use. Not advisable to use continuously without stopping because it might be counter productive.
Re: Mittens and Booties
I dont't wear booties for my son. I wore mittens for him until he was 4 mths because he scratches himself too much, once until he bled quite badly. He also had a tendency to poke his eyes. If my son doesn't scratch himself so easily, I think I wouldn't wear mittens on him.