I have a lot of frames (as icons) linked to one image (link). But now I want a glyph instead them. Is it possible to replace them with a glyph that I copied to clipboard? Any script? Even is it possible to track down a specific link with its path within InDesign?
Yes and no. If the existing frames have some object styles applied, you could use the Find/Change Object dialog and use "Contents of clipboard" as a replacing value. Otherwise, you could simply use the glyph as an external resource and relink the link to that file. Alternatively, you may want to use a script to do the replacements.