"Do you have any ideas, suggestions, or studies you have done for pitchers who throw from a low 3/4, sidearm, and submarine arm slot?"
In general, I am not a huge fan of side-armers and submariners. Some of this has to do the fact that I threw sidearm as a kid and now have a very sensitive shoulder. This is also due to my belief that, because of both how the human visual system works and the fact that the bat moves on a horizontal plane, a ball that is primarily moving in the vertical plane is harder to hit. The problem with throwing sidearm (less so for true submariners) is that most of the movement of the ball is horizontal, which makes it easier to see and keeps it in the plane of the bat longer.
On my web site, I have posted a study of Chad Bradford, who is a submariner...
I believe I have identified a number of things he does that have protected his elbow and his shoulder. However, I also think I understand the cause of his back problems.
"Do you think it is more effective for a sidearm pitcher to drop and drive?"
Let me answer this as two questions.
First, I believe that, if done and timed properly, pushing off of the rubber with the pitching arm side foot (the "drive" part of the question) can improve velocity by increasing the amount and rate with which the hips (and thus the torso and shoulders) turn. Having said that, my concern with the "drop" part of that question is that it will tend to flatten out the plane of the pitch, which could make the ball easier to hit. Since a sidearmer is already going to throw from a lower release point, that could be problematic.
Of course, Tom Seaver was a drop-and-driver and was very successful. However, I don't know if the idea would work for everyone.