Good to know that you can digitally sign PDFs in LO Draw, thanks!
Inkscape is decent for basic PDF editing as well, though depending on the font the textboxes can end up mangled when you edit them. The import is supposed to me even better in version 1.3, but I haven't had a chance to try it
Agreed - I think it needs to be distinct, but could still be an arrow. Maybe an arrow that curves to the right, like an email "forward" button? That's kind of how I think of a boost - a forward to everyone who follows me.