Using custom fonts for Chord symbols
It looks to me that in MuseScore chord symbols are locked to the single font.
However, there are other fonts now available on Internet that also use advanced font techniques (like substitutions/ligatures - I think that is the correct term) in a similar way as Marc Sabattela's font used for Roman numerals, and could be used as a viable alternative. MusGlyphs and MusAnalysis are very fine fonts developed by Dan Kreider.
In the attached figure is how font MusGlyphs renders tekst "Cdim0/Eb".
The problem must be in two things
1) How can MuseScore do the transposition when custom font is used
2) How can MuseScore do chord realization with custom font is used
However, this problems should note be unsolvable.