Nope! Four pound is plenty strong enough for any bluegill or crappie. I've landed lots of carp and catfish over 10# on 4# line. Besides, most lines on the market are stronger than what the label says. The box may say "4#", but it will probably break closer to 6#.
No, but I know of several good reels that will prevent line twist. I use Daiwa or Shimano reels that have some type of anti-twist device built into them.

