I'm still unfamiliar with using JSL for regular processing,
Again, this is done with the EmEditor.
document.selection.Replace("([a-Z]) ([a-Z])","\\1zzzz\\2",eeReplaceAll | eeFindReplaceRegExp,eeExFindSeparateCRLF);
document.selection.Replace(" ","",eeReplaceAll | eeFindReplaceRegExp,eeExFindSeparateCRLF);
document.selection.Replace("zzzz"," ",eeReplaceAll | eeFindReplaceRegExp,eeExFindSeparateCRLF);
document.selection.Replace("Is Missing\\(:(.[^)]{0,})\\)\\|","",eeReplaceAll | eeFindReplaceRegExp,eeExFindSeparateCRLF);
document.selection.Replace("!Is Missing\\(:(.[^)]{0,})\\)&","",eeReplaceAll | eeFindReplaceRegExp,eeExFindSeparateCRLF);