As long as your sticks are mounted to where the up axis is 90 degrees perpendicular to the screens lower edge, you're good. The physical orientation of the players shoulders doesn't really matter. It's all about the virtual world and virtual player you are trying to control that dictates the proper orientation of the controls. Take a look at Q-Bert as another example. That's one game where intentionally having the stick oriented different makes sense because those are the only true directions the player can move in the game. This again is relative to the virtual player and their virtual environment, not the physical players shoulders. As soon as you mess with that orientation relationship, it becomes unclear if pushing "right" moves your player up or down on a diagonal block.
You asked about what was wrong with some other layouts, and that took us down the stick orientation path. Anyway.... lets try to go back to your original questions in your first post. Given you already have a control panel built, I would first ask yourself, are you happy with it? If not what would you change and why? The only thing I saw in your questions that might be different is that you don't appear to have a trackball, spinners, (or a wheel) and don't have digital flight sticks to play something like virtual on.
I've never seen a single control panel have every controller under the sun like what you are suggesting. I think you really only have 2 options to accomplish that. You either make the panel that much larger to accommodate, or you think about clever modular additions. I'm on a similar quest but not looking to build the worlds biggest control panel. As others have pointed out, you have trade offs with aesthetic, "clutter", and general user confusion about what controls to use when you do that. If you have that much space and money, dedicated cabs is the easiest solution to properly support a game type.
For the virtual on sticks, if you didn't want dedicated 4 way controls, you could swap the 4 way control in the upper middle area of most panel designs with another digital flight stick and you could play it single player. You still have room there for a single spinner for games like tempest. You can put additional spinners near / above other player button clusters as well.
I've done testing in my build thread on trackball position and distance from other controls, so I won't repeat myself here. You should be fine for golden tee on a typical 48" size panel. Some of that depends on your play style but even with a big whack, it's generally fine. You do have to compromise a little on symmetry though to have the proper spacing, or you go bigger to accomidate.
Super Off Road presents a different challenge. If that's the only racing game you care about, you only need to worry about the wheel. You could add spinners sticking out of the front sides of your pedestal with detachable steering wheels. If you don't like the 90 degree mount, you could fabricate some sort of hinge lock system to pull them out and lock at the proper angle for super off road when playing, and lower back to 90 degrees when done. If you want to support other racing games too, then you have more challenges, as you need even more controls. Now you need pedals built into the base of the pedestal for each player you want to support. What about games like like road blaster or spy hunter? Now you need a yoke with button controls.
As for space between players and controls, I wouldn't go any tighter than 18.5" between joystick center to joystick center unless you add in physical rotation of the player.