Some ghosted nodes seem to get stuck with neighbors that never go away, not sure why. It usually is other nodes which cannot have a repair done on them (battery or dead nodes). So if tey are all neighbors of each other those may never go away. (Also if their only neighbors are other dead nodes they are probably not doing any harm to the mesh).
Your other option to get rid of them is using brute force with a USB stick secondary controller. Here is guide about it: How To: Remove Z-Wave Ghosts (including using a UZB Stick)
One other option I had thought of but I don't think anyone has tried, would be to do a z-wave replace on those nodes. The idea would be to some other extra device paired to that node using the z-wave replace feature. Then once it is paired, you can do a proper exclusion and remove it fully. This should, in theory, work perfectly. You just need an extra Z-wave device to do it with. Here is my guide on using Z-wave replace: [Guide] Updating Firmware and ZWave Replace - #2 by eppower
