Please help with identifying this disease

[arcticfox]

Hello everyone, need some help with a fish disease. I have a small to medium gem tank that I have had for about 2 months that believe has Lymphocystis.
back ground with this fish. When I received the gem tang he was in quarantine with 4 other tangs for about 3-3.5 weeks. While in quarantine they were all treated with furan 2, a therapeutic level of 2.25 copper and prozy pro.
On the day of transfer to display tank I noticed 1 tiny dot on the fin of the gem tang. Over the last 2-3 weeks in Display tank the spot has grown in size and now has moved to his body where the fin touches the body. Today I noticed one of my purple tangs started to get it on a single fin. The fish are in a 200 gallon newly established tank. If anyone has any other thoughts with what they believe this could be please fell free to help me out. I would like to try to get the fish into my 2nd hospital tank and I have a power blue and fox face in the quarantine right now. If I can not remove fish from display would I be ok to leave in display tank for if it is lymphocystis I believe it is a waiting game with no kind of treatment. These are the best pictures that I could get

 

[arcticfox]

Forgot to mention while the gem was in quarantine he got to close to my mp10 and was stuck on the side for f it. I do t k ow for how long but his Dorsal and rear fin was shredded and caused Popeyes. Popeye only lasted about 4-5 days. I read lymphocystis can happen after a fish gets popeye.