It depends. If the frames/Textures used to create the icons are made by your addon, you can use a mixture of
https://warcraft.wiki.gg/wiki/API_Frame_SetFrameStrata
https://warcraft.wiki.gg/wiki/API_Frame_SetFrameLevel
https://warcraft.wiki.gg/wiki/API_Region_SetDrawLayer
to adjust the latering of the various parts.
If the icons are being created by a provider like HandyNotes it might be best to see if the documentation or someone using/authoring that addon might be able to provide a better solution.