Regarding that beaming issue. You can do that by using two visual staffs, both muted, and one hidden, that plays the music correctly.
First staff might be looking something like:
!NoteWorthyComposerClip(2.0,Single)
|Clef|Type:Treble
|Note|Dur:8th|Pos:-3|Visibility:Never
|Note|Dur:8th|Pos:-3|Visibility:Never
|Clef|Type:Bass
|Note|Dur:8th|Pos:-3|Visibility:Never
!NoteWorthyComposerClip-End
And the second staff something like:
!NoteWorthyComposerClip(2.0,Single)
|Clef|Type:Treble
|Note|Dur:8th|Pos:-3|Opts:Stem=Up,Beam=First
|Note|Dur:8th|Pos:-3|Opts:Stem=Up,Beam
|Note|Dur:8th|Pos:-3|Opts:Stem=Up,Beam=End
!NoteWorthyComposerClip-End
Then layer the two.
The third, hidden, staff is just a repetition of the first staff.
Possibly a pain the the you-know-what to maintain, but it seems to be working.