I think you have plenty of everything! Doublers will not be needed for awhile, if at all. I haven't needed any other then at night time, and now we don't need them for night time either. I had 6 nb covers and that was plenty.
Here is sort of a side question for those of you who used longies at night with a NB, what did they wear on top? I'd be scared, still am :LOL, to put my baby in a shirt that isn't held down. If its lose I'd be afraid it would move up and suffocate her, if its a tight fight I'm still afraid in the winter that it will ride up and her tummy won't be covered and she'll get cold. DD always wore a onesie and a warm fuzzy sleeper at night in the winter time.