To answer about organization of staves: It's the way that Sibelius organizes it. If I try and change it, Sibelius gets very angry and puts tempo markings inside of the trumpet staves. Idk why.
I know there is no viola, made that specific setup without one for some reason. The current piece I'm working on does include one 🙂
I often keep flutes 1,2 oboe 1,2 etc separate because writing them as one stave is super annoying and takes more time than it saves. It also helps my workflow, imo.
In many scores I have seen Trumpets using key signatures, and although I do know horns don't usually have a key signature in orchestral works, I give them one so it's easier to write. I can always change it to F and Sibelius will automatically update accidentals, thankfully.
If you're implying the dynamics don't work unless you hold down ctrl to type them, they do indeed still work.
I thought tutti was for all sections to indicate the end of a solo? In band I recall the composers of our pieces of music using them (if I remember correctly).
A Tempo Meno Mosso is saying to play the original tempo but a bit slower, exactly as it implies.
I know it should be bar 1 but I forgot how to fix it, and knowing this will never get played I didn't bother with it.
Flutes can go as low as Sibelius says they can, they produce a different effect and do different things, obviously.