Is it possible to share the library part or a screen shot of the device and symbol from the library?
I tried doing this,adding an attribute to the device and part, and clicking "reposition attributes" then left clicking on the part makes the new attribute appear. (i have 9.4.2)
Right clicking and selecting the option you mentioned _also_ makes the new variable appear.
The option you found might still be able to be run on a group because it should be the equivalent of a "shift + click" on the part (see help reposition). So to try it on group, just type this in command line
group all;
then press enter
reposition (s> 0 0);
then press enter
See if that works. I cant tell because on mine both Reposition and Restore position have the same effect in that the new attribute is added.
So the steps i follower were:
Add attribute to device in library
Add attribute text field to symbol in library.
save library
update all library in schematic
use reposition attribute or restore position on said parts and the attribute apppears.
also just fyi regarding this:
"If I manually replace a part in a schematic it removes it from the PCB! I really do not want that! Is there a way around that?"
This is not true actually. If you use the "replace" command, then the new part is positioned on the pcb the same place/orientation/connections as the original. Try it on a copy of one of your projects to see.