1) Can we upload a pdf instead of screenshots for the sheet?
Yes, I would prefer to have it as a pdf rather than screenshots if it's sheet music as well.
2)the program I use to write the midis is a little old and wanky in some aspects ( guitar pro 5.2 plz dont shame me XD) and, for example, if I tune down an instrument (a guitar in D standard) it still show the notes like it was in E standard tunning so my question is: Should I send 2 audios?(like a midi that matches the sheet and a real reacorded mp3 in the original tunning) or Im fine just sending the recording and claryfing that detail in the sheet?
You're fine just sending the recording and clarifying that detail in the sheet ^^