Those ingredients will treat most protozoan issues but I am not sure it is parasite Benjie. You had the wilds for 2 weeks and saw no symptoms. Usually when a fish has something like velvet they breakdown in the first week of being received because they have had their slime coat stripped off in handling.
I am not a fan of copper meds in acidic water , as they can be toxic so watch out for signs of toxicity.
If it were me, I would use NaCl salt at 1 tabelspoon per 1 US gal water. Full water changes daily and replace the salt for up to a week. If after a few days theres no improvement I would use furan 2... That would be my line of attack here. If these failed than I would consider the parasite route. Basically it comes down to how one interprets a set of symptoms that are common when discus deal with pathogens.
Good luck!
Hth,
al