1) Use high viz line and learn to watch for your line to jump. You will feel the thump most of the time, but sometimes you will just see the line jump. The ones that make the line jump, but you don't feel tend to be better quality fish. I'm not sure why that is.
2) That's up to whatever you prefer. I use a 10' Sam Heaton super sensitive for that purpose and I love it. I held an 11 footer, but it felt considerably heavier where as the different between 9' and 10' wasn't as drastic, so I went with the 10'.
3) I haven't used minnows in years, but there is no denying that they aren't effective. There is nothing wrong with either one.
4) If fishing below a float, I tend to hook them through the back. When tipping a jig, I hook them through the lips. I'm not sure it really matters, but that is what I do.
5) Fluorocarbon sinks and mono floats. Most serious crappie anglers use the hi viz mono and braid. I use hi viz on my dock shooting setups and 15# Power Pro for dipping heavy brush. The braid is so I can straighten my hook and get more fishing time in instead of breaking off and retying all of the time.