I have seen through the Inkscape video that Rotate Copies, Mirror Symmetry does work with paths as well as groups. Does the latest Windows Alpha has the working features of these or is it just on my end that's the issue? On my end, those do not work with groups. I'm using the 64 bit edition. Gonna try out the latest 32 bit edition.

It depends a bit upon what is inside the group (for me, on Linux). It does not appear to work with all shapes (I think it didn't work with circles in a group for me). After turning all shapes in the group to paths, it did work in the development version last time I tried it out (a few days ago).

I actually tried out your suggestion, it does seem to work. If only they're more like transformation tool, but I can wait for those LPEs to be improved one day. Thanks.

I believe that Jabier (the developer who wrote the extensions / made the video) likes to get user feedback on the features he added.

You could make a feature request at https://bugs.launchpad.net , where you describe the problem you had / have and suggest a way to improve the LPE (from a user's point of view, not for the code).