Finale v27, v26, v25; Windows 10
Assuming nothing's changed since v25.5 in this area ... Document Options > Music Spacing > Grace Note Spacing > Keep Current
I have no idea what's in Notepad .... so here's the online manual for Finale Notepad if you haven't already found it. https://usermanuals.finalemusic.com/NotePad2012Win/NotePad_Left.htm#CSHID=0|S...
Not sure about an automatic setting for this, but it is possible to do. Select the Page Layout Tool, right-click the system you want to edit. Enter a positive number into the right-margin field.
I use the built-in plugin for this sort of thing. Plug-ins >> Note, Beam, and Rest Editing >> Move Rests... >> Select "Clear Manual Positioning"
Note that fixed-sized lyrics don't space well. Also, the lyric size does not change (for me) even when I reduce all of the "noteheads" in a chord. It will resize if you reduce the "note or rest."
It seems like you'll need to "ungroup" the "shape" and reposition/resize accordingly if you are looking for a solution within Finale.
How did you buy Finale v26 last year?
How are you editing the multimeasure rest? Locally (right clicking on the measure) or globabally (document options)?
Not sure what you are experiencing, but it works for me in v25.
Is there a "Page Layout Tool" in Songwriter? Check to see if there are any page breaks on the pages with few systems. Also, I'm not sure if you can lock measures but that's something else to look i...