I would say no.
depends on what type of paper airplane you are trying to make. wide winged are better with hard paper like printing paper and narrow ones doesn't matter. (just my personal experience not so trust worthy)
The effect of a hole on a paper airplane would depend on the type of paper airplane the hole is on, and where it is on the aircraft.
Wax paper works good for strong, high-flying planes.
no
Generally, it is optimal to make a paper airplane symmetrical. I am not sure I understand what you mean by type of symmetry. However, some paper airplanes can be designed to be asymmetric and remain straight flying.
no
Well, if you want a certain TYPE of paper airplanes, and how many are there of that type, ask that. There is no real answer. A paper airplane is probably being made right now!
aerodynamics
I know!
it could affect it because depending on the wing span, if they are wider then usual to catch more air.
gliders
the lighter the paper the easier the lift.Heavey paper will drop quicker.