Non linear throttle response is not unusual in aircraft engines, both jet and piston, that being said it should not be a struggle to find the desired setting.
Yes, but the German Throttle in the 109 G-2 was the same like in the F-4. You had distinct positions for distinct manifold pressure/rpm positions. Only the last position the Emergency power was blocked, so you couldn't put the lever on that stage.
In BoS its comepletly wrong modeled. Actually the throttle ingame should have a deadzone above the 1.32 or 1.3 ata setting. That would be historically correct.