G'day Carlsson,
the phenomena you report is known in a general sort of way...
What's actually happening is that the NWC implementation of a grace note is not "according to the rules".
An appoggiatura (grace note without a slash across its stem) should steal time from the following note according to some fairly complex rules depending on whether the note is dotted or not. Without going too far into that suffice to say that it (they) should steal around 50% of the following notes duration.
In NWC, a grace note is fixed at a 32nd note (demisemiquaver) duration. Thus if you have enough grace notes to add up to a duration longer than the note they precede then you will get the phenomenon of some grace notes playing after the principle note.
Demisemiquaver demo:
!NoteWorthyComposerClip(2.0,Single)
|Clef|Type:Treble
|Instrument|Name:"Trumpet"|Patch:56|Bank:0,0|Trans:0|DynVel:10,30,45,60,75,92,108,127|Pos:9
|Tempo|Tempo:60|Pos:12
|TimeSig|Signature:2/4
|Note|Dur:32nd,Grace|Pos:-1|Opts:Stem=Up,Beam=First
|Note|Dur:32nd,Grace|Pos:0|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:1|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:2|Opts:Stem=Up,Beam=End
|Note|Dur:Half|Pos:3
|Bar
|Note|Dur:32nd|Pos:-1|Opts:Stem=Down,Beam=First
|Note|Dur:32nd|Pos:0|Opts:Stem=Down,Beam
|Note|Dur:32nd|Pos:1|Opts:Stem=Down,Beam
|Note|Dur:32nd|Pos:2|Opts:Stem=Down,Beam=End
|Note|Dur:8th|Pos:3^
|Note|Dur:4th|Pos:3
!NoteWorthyComposerClip-End
Overlap demo:
!NoteWorthyComposerClip(2.0,Single)
|Clef|Type:Treble
|Instrument|Name:"Trumpet"|Patch:56|Bank:0,0|Trans:0|DynVel:10,30,45,60,75,92,108,127|Pos:9
|Tempo|Tempo:60|Pos:12
|TimeSig|Signature:2/4
|Note|Dur:32nd,Grace|Pos:-1|Opts:Stem=Up,Beam=First
|Note|Dur:32nd,Grace|Pos:0|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:1|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:2|Opts:Stem=Up,Beam=End
|Note|Dur:Half|Pos:3
|Bar
|Note|Dur:32nd,Grace|Pos:-1|Opts:Stem=Up,Beam=First
|Note|Dur:32nd,Grace|Pos:0|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:1|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:2|Opts:Stem=Up,Beam=End
|Note|Dur:4th|Pos:3
|Rest|Dur:4th
|Bar
|Note|Dur:32nd,Grace|Pos:-1|Opts:Stem=Up,Beam=First
|Note|Dur:32nd,Grace|Pos:0|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:1|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:2|Opts:Stem=Up,Beam=End
|Note|Dur:8th|Pos:3
|Rest|Dur:8th
|Rest|Dur:4th
|Bar
|Note|Dur:32nd,Grace|Pos:-1|Opts:Stem=Up,Beam=First
|Note|Dur:32nd,Grace|Pos:0|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:1|Opts:Stem=Up,Beam
|Note|Dur:32nd,Grace|Pos:2|Opts:Stem=Up,Beam=End
|Note|Dur:16th|Pos:3
|Rest|Dur:16th
|Rest|Dur:8th
|Rest|Dur:4th
|Bar
|Note|Dur:32nd|Pos:-1|Opts:Stem=Down,Beam=First
|Note|Dur:32nd|Pos:0|Opts:Stem=Down,Beam
|Note|Dur:32nd|Pos:1|Opts:Stem=Down,Beam
|Note|Dur:32nd|Pos:2|Opts:Stem=Down,Beam=End
|Note|Dur:8th|Pos:3^
|Note|Dur:4th|Pos:3
|Bar
!NoteWorthyComposerClip-End
As far as the fermata is concerned, it has its effect when the note it is attached to is played. Thus if your principle note plays when, say, the second grace note plays then you have a 2 note chord that is paused. Fermata duration concludes and the rest of the grace notes play.
Your examples show this.