Understanding Ignition timing

[Bronzer]

im writing an essay on the effects of ignition timing for college. theres just a few things i would like someone to clear up for me as im getting a bit confused.

air/fuel mixtures burn at different rates under different pressures?

low octane fuel burns quicker and less evenly?

increased VE would result in an increased advance of ign timing. (assuming its at the same RPM)?

maximum pressure should be made at 10deg after TDC, does this mean that that is the point which combustion should be completed and thus the maximum pressure from the released gases will be availiable to produce torque?

cheers.