On Wed, 28 Jul 2021 at 20:20, Francesco Petrogalli <firstname.lastname@example.org
> Hi lilyponders,
> I have written a modification to a piece of mine in which I provide
> variations for some of the parts:
> For the following instruments:
> clarinet 1 and 2, contralto 1 and 2, tenor, euphonium
> The score has two versions, one that uses tuplets and one that does
> not use tuples (tuplets over 2/4 are not easy to march in a band).
> The issue I have is that, although I marked the alternative parts as
> "alignAboveContext" , the small staff is printed above the
> correspondent staff only in the conductor score but not in the
> individual parts. 
Please try to make a minimal example. Usually when trying to reduce your score to a minimal example showing the issue you might find the solution yourself.
I suggest you to use the last version (stable or unstable) because 2.20 is not the latest.
You need not have a Staff named "clarinet1" if you want something to align above it.
I haven't found any \new Staff = "clarinet1" in your code...
> I am also unable to print the key symbols in the small variation
> parts. All the flats/sharps are rendered inside the measures instead
> of being specified in the beginning of the staff.
I guess that's because your transpose is applied to your key signatures as well.
\transpose bes c' for a score in B flat major (\key bes \major) lead to something in C major, hence no key signature.
Take your \global out of the transpose if you want to keep a B flat major for your separate parts as well (but this is not standard practice AFAICT, both the notes and the key signatures are transposed usually).
Hope this helps.