The lesions on the severum do look to be compatible with "hole in the head"/head and lateral line erosion. The white areas are actually usually areas of depigmentation from the skin damage and not a fungal infection. Would have to do a skin scraping tfrom the affected area to be able to tell for sure.
Fish died last week, it also developed popeye in both eyes. I lost another gold severum today. It developed a big hump on its head between the eyes which was full of white puss and also developed pop eye in both eyes.