PlayScore 2 is designed to allow the musical director of a choir or ensemble to create practice resources for singers and players.  Play-My-Part and Music-minus-one arrangements can be shared with others free.  The director needs a subscription to make the practice scores, but the singers/players can play and interact with them free.
Once you have scanned the music, save it as a PlayScore document to iCloud, Google drive or Dropbox and import it back into PlayScore 2 once for each part.  Add part names to the title as you go.  That gives you one document for each voice
Adjust part volumes for each voice-document as appropriate (see Play-My-Part)
Lock each document (tap lock symbol) and email them to the musicians:  Tap Select, and then tap the document (long-tap on Android devices).  Then tap the export icon and choose ‘Save/Share Document’.  When you see the sharing screen select email and send
Your ensemble members should first download PlayScore 2 on their iOS or Android device.  They won’t have to pay.  When they get your email they tap on the attachment and choose ‘Copy to PlayScore 2’.  They will then be able to interact with the music just as you did.
Creating MIDI tracks
PlayScore 2 playing-scores are best for iOS or Android devices.  But if you need to listen on a PC, you can still create MIDI files with parts separated that sound just the same.  Any device or desktop can play a MIDI file so this option works for people with Macs or PCs.
Tap Select (long-tap for Android) and then Export as before, but this time choose Save as MIDI
Send, for example by email
On most devices the recipient can play the MIDI just by tapping it.