What's in the case - The Billiards Doctor 

1) Ferrule type is sort of standard for playing shafts unless you have Revo which does not have a ferrule. The ferrule contains a special foam inside of it which gives the cue a little more feel. the Phenolic ferrules are reinforced for break cues specifically so they do not break but also so they give that extra power since they are not as hollowed out with that foam as standard playing cue shafts are. 2) Ferrule length has been a thing of controversy, but it seems that most cue companies are shifting to the shorter ferrule length. I think this is because the ferrules are known to increase feel but also do not follow the same physics for deflection as the rest of the cue. With better technology and foam that is used, cue companies are able to have a shorter ferrule which has the same feel as previous ones, and now the shorter ferrule means that more of the cue can follow with the low deflection technology implemented by these new low deflection shafts. Since as you move closer to the tip of the cue, the more important those parts of the shaft are in determining deflection characteristics of the cue. 3) interesting. I have not heard much about all the different types of ferrules offered, but to be safe, I would stick with the ferrule that comes with the cue instead of changing it out. As far as I know, i dont think professionals get these fancy ferrules. These other ferrules could be gimicks? Or maybe they aren;t but I would think that the idea of changing them out could bring a little error that would probably end up canceling the benefit of these new ferrules (if there is any benefit from them in the first place) 4) You are correct that in theory a softer tip allows you to grip the cue ball more to get more backspin since this extra "grip" allows for more contact time with the cue ball. As for side spin, I believe this would be the same concept, and I believe that you are right, but I have never tested this out personally and have not heard of this being tested out. This theory does make sense though as when making a long straight shot, you want as little side spin as possible, and it is widely known that a harder tip allows for a much easier time making long shots. So a softer tip inducing more side spin on the cue ball when shot slightly off center would make sense. I personally prefer harder tips (like tips that are medium but a little harder than standard medium tips), because I generate plenty of spin with the medium tip, so a soft tip would be overkill on the spin, but I can definitely make longer shots much easier with the harder tips, so for my game, the medium tip is good.