For line to line transitions i mostly use expressions.. I posted a fade-in/fade-out expression somewhere in this thread (try understanding it lol). I bet you can do some weird random offscreen jumping too with expressions, because it's just related to the thisLayer.outPoint variable (most of the time). Otherwise it's keyframe's
And those keyframe style's could be correct yes :P Never really remembered what does what, I just try it and see if it looks nice..
About that clonestamp tool; never used it. I always used keying for getting alpha channel info (if that's what you want), will look into it tomorrow or so.. (isp (kpn) stole my internet connection at home :|)