Since I'm working with diplomatically transcribed medieval manuscripts in German in my thesis, stuff like vͤ (v with e superscript) or uͦ (u with o superscript) appear frequently, and these aren't present in the bold italic style. For the time being I'm using \stackrel to manually align the missing superscripts. This doesn't look perfect (superscripts are too low and slightly off to the left), but it works. I'd be glad if native combining superscript letters were added sometime.
Yes, exactly. It's a very interesting letter shape.
Ligature of round d and e
Access to precomposed accented metrical symbols