I had to experiment with my scans before they were the way I wanted them.I am no expert in this but, I know that in my case,jpeg format with a medium resolution was fine.
As far as leadsheet is conscerned,MidiNotate will read the midi in a full window showing all tracks. You pick leadsheet,and the melody track,and you get a single staff melody line with chords above,and a moving highlight of the note being played.If you want to add another track,it displays that on another staff below.
Re repeats etc on the fly,It is a bit more cumbersome than merely looking at a scan. You can tell it in advance how many repeats etc.The other way is to put the cursor at the beginning,or anywhere else and it will repeat from there.

I don't know of any universal format either.Since the program converts the different tracks to a leadsheet,it takes the same program to run it.

To have the best of both worlds,would be to run a laptop and a Musicpad,but the Pro is too expensive for me.

Bernie