1). Easy answer. Never restart after a bad first ball. Some of my best GC scores have come after a terrible first ball. If you restart after a bad first ball on this game in particular, you're going to be restarting more games than games you complete. That being said, if you're on ball two and hold in the start button, a new game will begin.
2)yes. I always get my BB close, start a MB, then keep hitting drops with the ball saver on to start BB.
3) I try to never hit him straight on. I have had luck by glancing off the left or right side of him like you would do to the Iron Monger on IM.
4) during prison MB, all the main shots are jackpots. Once you collect one, they go out, and you must hit the Prision to relight them. Well walker jackpots are built up from any switch hits on the playfield I believe and collected by hitting the well walker.
5). Read up on how to use the shot multiplier effectively (inlane lit X). Buy saving this for the right time, you can get shots worth 50-100 million fairly easily before you even get to a multiball.