A melinus is your worse choice of a display animal. Your best choice was your original choice, an argus monitor.
Unfortunately they are not the best for handling in front of groups of people. Argus have a mind of their own and will want to go play with the people. Which is why they are a great display animal.
The best for handling is a Sav. They are so, because its their natural behavior to lay low and let the threat go by. Which means to sit still in adverse conditions. Taking them away from their homes is indeed adverse conditions. Monitors are homebodies, all of them. Taking them out of their scented home area is stressful. Its how they react to this stress that is what your really judging.
Taming any wild animals is taking their natural behaviors and mutating/aborting them to satisfy human entertainment values. None of these animals WANT to be used for human entertainment, be it a whale or porpoise or monitor. They would always choose to do otherwise.
I understand that you call taking animals to classes and malls/fairs, education. And you can call it anything you like, but I get the feeling is 99% of the time, its only entertainment.
How about making videos of them(these monitors) in nature, and in captivity, showing them doing normal life events, IN BOTH. You know, borrowing, climbing, feeding, breeding, hatching, growing, and of course another normal part of natural life, dying. Showing that in both captivity and in nature would indeed be EDUCATIONAL.
So do the needful and oblidge, use an argus and clip its nails. They are the most mentally strong and can put up with our silliness. Cheers