I knew or understand (1) and (2) on your list, 3 and 4 are new to me or haven't thought about cue ball weight VS less or more deflection.
Mix chickens and bricks
Not a problem....
Cue ball weight plays a big factor if you ask me. A heavier ball deflects less, both off the cue tip and off the object ball if you aren't hitting the object ball straight on. When you are playing the angles of the table for position, you must make an adjustment for the difference in angle the heavier cue ball comes off the object ball as you are playing position. I think you can get more "feel" of the cue ball when you are using a solid maple shaft...I think it resonates more...tone, if you will.
The key to playing well is understanding what "tone" is most favorable for your style of play. If you like to play "ping pong" style (back and forth all over the table, get a harder tip and a shaft that will make the cue ball come off the tip faster...I think a stiffer shaft does this. If you play a softer game where you try to spin and caress the cue ball around the table, use a softer tip and a shaft that bends a bit where it will let you "pull" the ball around the table with spin.
If you play like I TRY to, I play "no spin". For ME, the most comfortable shaft is one that gives me a mixture of both...a medium tip and a shaft that has flex, but not so much that it spins the ball by itself (many of the new LD shafts have this as one of their main selling points). Once you have developed your stroke, you will realize that spin isn't always the best way to create angles. Use natural angles as much as possible and let the cue ball "float" around the table.
I don't want to derail this thread, but players must understand that NO shaft is perfect for every player or even every situation. I can play with pretty much any cue, but I had rather play with a cue that I already know is tailored for my style..
I was playing yesterday with two of my cues (I try to use the same cue as much as possible to keep a consistent feel, but since I play only on Sundays my feel is gone from one week to the next) and when I realized that I was hitting the ball good but with not enough "oomph", I switched to another cue with a bit more forward weight and a bit stiffer shaft. They both had the same tip (TNT Max Pro) so the feel was "similar". By similar, I mean the way I could hit the cue ball in the same spot and get the same "resonate" tone that I could "feel" in my hands and I could judge it by the reaction of the cue ball when it came off the object ball.
The key to a shaft is to get something that "fits" YOU. You have to "know" what feel you like before you can ever decide what type of shaft is best for YOU. Some people swear by LD vs non-LD. I swear by "feel"...if I hit the ball and get the right feel, I know almost automatically that I have hit the ball good because my cue feels like I've hit the "sweet spot", like you feel when you make a good shot with a tennis racket. You don't always hit the ball over the net when you have hit the ball good, but you almost ALWAYS know when you have hit it bad...because you don't feel the same "resonation".
Aloha.