Can a charcoal grill maintain a constant high temperature?
The recipes you are referring to are probably for BBQ/smoking, rather than grilling, which happens at a much higher temperature.  It is fairly easy to get a kettle-type grill to reach 400 F (and well beyond).  The challenge will be maintaining your desired temperature.  However, that is what the vents are for.  There should be a vent on top and a vent on bottom.  With a little practice, you should be able to manipulate the vents to maintain the temperature.  Try to overshoot your mark by 25 - 50 degrees F before you reduce the airflow. You will get some smoke flavor from the charcoal, particularly if you use hardwood. The addition of smoking wood will add stronger smoke.  For vegetables, I would stick with fruit woods.