Sorry, can't help you on the shock ID--need to get info from someone with more specific information as to part numbers.
I would be less concerned with the compression of the left front (although it does not seem very "stiff" judging by the crude "stomp on it" method)--I would be more concerned if the right front or right rear "bottomed out". My experience is that very weird things happen when suspensions suddenly become "solid"--many times leading to loss of control. The loads on the right side are more likely to cause that problem yet I have not heard of anybody experiencing suspension "bottoming out" with the spring/ride height combinations you indicate.
If the shocks have insufficient compression damping or "bump" resistance, you should be able to tell that by testing them off the car. I can say that my new shocks from INEX this year are quite stiff in compression.
In the past, I've worked with Penske in configuring custom shocks. I've not seen shock dyno data, but I think the Legends car shocks from INEX have sufficient compression damping for dirt cars---I wish they had a bit more damping under rebound. IMHO as an engineer, their rebound setting allows a relatively rapid rate of weight transfer in roll and contributes to the car having a bit of twitchy feeling.
The handling complaints you have could possibly be caused by weak shocks--but I think they would have to be so weak that you would notice by a crude manual off the car push by hand test.
Here's a crude method that has worked for me: I lean over and (I weigh 200 pounds) push the shock down as hard as I can against a bathroom scale. (Use a block of wood to distribute the weight so it is not a "point load" and so it does not damage the scale.) For my Legend shocks, the shock will compress at a consistent speed and the scale will read between 100 and 110 pounds. It will take just about a second to fully compress. ) If the shock is worn out, the scale reading would be much lower and the speed higher. If the shock is bent or the cylinder is damaged, the reading would be higher and the speed lower or jerky--you would sense it binding up.