Discus can take time to settle. Then can be skittish until they get comfortable with their environment. My tank is in a very high traffic area. At first fast movements could spook them. After some time they rarely ever get spooked.
The bigger question would be are you able to maintain proper tank cleanliness and water quality, with your existing decor, to properly grow out your juvies. Do you have photos of your tank? Do you have substrate?
Your fish will very quickly outgrow that tank as well.
Also QT is extremely important