use accessory weapon != game event action. I don't know what the game event do, but I think it's mainly book keeping
the weapon range on the molly is still 15 even if the ability range is 20. In this case the weapon range limitation wins out.
The delay in the spawning of the projectile is what determines how fast you through it. As both grenades when flying through the air are not actually the weapon, they are just a projectile linked to a weapon.
I don't really have time (since it's 1 am....) to go in game and test to perfectly time every grenade but as far as I can tell windup doesn't have any relation to throw time because Volks throw takes long than .25 seconds (which the weapon indicates as it's wind up time...)
Regardless, in it's current state the Flame Grenade on Volks is not worth 37.5 munitions.
Have to upgrade to molotovs.
The cost of upgrading is less than your starting fuel, getting flame grenades be it on Cons or OKW is free.