What is the equivalent height of a parachute landing?
As you have intimated in the question, how hard you hit the ground is very dependent on a number of factors.

When I did my training to jump using a classical tethered round chute we practiced landing from a platform of about 5 feet, so six is perhaps a hard landing. That's, roughly, hitting the ground at 12mph. 

Folks like the Red Devils typically use an parafoil chute. Basically a self inflating wing. These can be steered and pitched upward to bring the trooper to a stall or even go up if they have enough forward velocity. So yes, you will often see them stop in mid-air and step down. This means this type of parachute has NO equivalent jump height. In fact if flown incorrectly you can crash into the ground at serious speeds.



Regular "military style" parachutes provide no control over lift and only minor control over direction. With these your descent rate is totally dependent on size, weight and air quality. 



Interestingly, with a regular chute, what makes landings "harder" is not so much the effective height but the amount of horizontal velocity.

You are trained to drop and roll when you hit the ground to absorb the impact. 



This works great if you have any horizontal velocity to help you initiate the roll. If however you are coming straight down it's not so easy.. and your knees end up in your chest...  as I found out the one and only time I jumped out of an aging Cessna.  Too much horizontal velocity and that roll gets rather violent.