So this will include midi file attachment per song ie as a midi player?
Yes, you will be able to attach SMF files to songs, the same way you can do with audio recordings. Basically SMF becomes a supported audio format alongside MP3, AIF, etc.
Please allow default sound font system wide, with option to add another selection per song.
Initially you can just have one SoundFont selected in your settings, but adding more SoundFonts at the song level is on my wish list.
Also thought if there can be sheet music or music linked to the midi file playing
ie maybe can use automation to show lines/sheet music
The new functionality will also support MIDI data files to send commands to other devices in real time. Ultimately I'd like to let MIDI commands in the attached file drive actions in the app -- so you could build a MIDI file as an alternative to an automation track. But there's a problem I would need to solve with that first. Until then, you could do this with an automation track.