Hey there.
The only plugin from that system that I know it works with is the weapon swap plugin, and only if you download the included patch. Even then, it doesn't work very well at all, especially in the menus.
Olivia disabled dual wielding in that plugin (probably in the other octopack plugins as well), either because in a true octopath-based battle system, there would be no dual wielding, or because there was some kind of issue with dual wielding she couldn't fix.
In either case, as I only own a copy of the weapon swapping plugin, it is the only one I have made a patch for. Since it appears from that plugin alone that Olivia didn't want dual wielding in the octopack, it's likely it's been disabled in one or all of the other plugins as well, and probably causes even more issues with them if you were to use my patch.