Yes. For example, in Japan, resting your chopsticks by leaving them stuck vertically in your bowl of rice, and passing food directly from your chopsticks to someone else's chopsticks, are both discouraged because they remind people of funeral customs.
In China, especially in the northern provinces, sticking chopsticks vertically into food is also reviled by adults, as this method is only used to offer sacrifices to deceased ancestors
Yes. Besides the grip (where the standard matters more), Japanese food culture emphasizes particular ways of picking things up. Stabbing a piece of food with your chopstick is considered poor manners.
I believe this goes back to the ancient Shinto belief that all beings are inhabited by kami (gods). Therefore to pierce a food is to pierce the god within. This is also why origami developed more broadly in Japan, because paper cutting (a Chinese artform) would damage the kami whereas folding fortified the kami. That is why much origami is of animals. There is also a belief that all food prepared in Japan is given "as is": a crafted piece given down from a master sushi chef, a wagashi artisan, or a tonkatsu expert. Sliced, shaped and formed as a bespoke morsel for the diner, not to be tampered with, but to be appreciated whole.
The "roll" angle (as in roll/pitch/yaw) w.r.t. your elbow is relevant.