What i want to achieve is a wikipedia style citation (like so Biblatex supercite command with use of square brackets (like a reference style in Wikipedia) ). At the same time (to handle the problem with add. postnote information) i'd like to to have postnotes i passed along to be added as footnotes. A very nice code snippet for \supercite with footnotes has been posted: Biblatex cite with footnote only once, with use of brackets.
So how can i extend the first code snippet to pass postnote arguments to footnotes (in a style that resembles the second code snippet)?