TargetTalk

1. The position of my elbow in my ribcage influences my zero position
2. If I rest the rifle more on my point-and middlefinger, than its more stable, but hand is more difficult to relax. More towards pinky is easier to relax
3. If have the feeling that too much weight hanging off my right hand (holding the pistolgrip) makes it less stable and recoil is a sideways/circular motion. Too much weight, cause for instance, the rifle is too front heavy

1. Absolutely. Everything you do effects NPA, some more than others.
2. If I understand your question correctly; the difference in forearm angle/hand angle is what makes one hand position easier to relax than another? As you change position on the hand you change the angle of your forearm (unless you compensate with elbow placement, but then you have changed the other relationships like elbow/shoulder/forearm angle and possibly balance, which might make relaxation different) which will have effects, and possibly the ones you mentioned.
3. If I understand correctly; the rifle is twisting in position due to "too much weight hanging off my right hand" and thus effects recoil? If this is the case there are at least 5 adjustments you can make:
a) Change the setting/angle of the pistolgrip
b) Change the angle of the entire rifle.
c) Adjust how you hold the pistolgrip without adjusting your relaxation level in the arm/shoulder
d) Adjust the relaxation level in your arm/shoulder by lifting the arm to a level that doesn't create the twisting motion.
e) Adjusting the length of the buttstock to some degree.
This answer is probably not what you were looking for, but this is how I understand the question.

As I'm sure you understand, it's hard to assess the issues at hand completely over the internet so in case my answers are not what you were looking for, I apologize.