Can hand brake levers be pulled hard enough on a comfort/cruiser handlebar?
You will have no problem with the brake levers. The force you apply to the levers is between your fingers on the lever and the palm of your hand on the bar grip, so the angle of your hand with respect to you body does not matter very much.

If you want to convince yourself, sit on your bike, turn the handlebars slightly so the bar is at an angle less than 90° to the axis of the bike and squeeze the brake lever.