You gotta attach your hp and health strings to some helper frame and set higher frame level for that frame.
example:
lua Code:
local h = CreateFrame("Frame", nil, self.Health)
h:SetAllPoints(self.Health)
h:SetFrameLevel(10)
self.Info = SetFontString(h, main_font, main_font_size)
self.Info2 = SetFontString(h, main_font, main_font_size)
Using same method you can create such helper frame for icons and set lower (or higher, depends on your needs) frame level .