With the right paint job you can work with more than just actual ghost models. At one stage I was using the Dryad models as generic lesser daemons. All it took was trimming off all the leave and wildlife bits and then I painted them to look like purple hued shadows with yellow eyes.
The Bladegheist Revenants would work quite well if you wanted to count them as bloodletters, and you could run Dreadscythe Harridans under the daemonette rules. Characters would be fairly easy to work out counts as for, and you could go with larger Death Alliance models as larger daemons. Morghasts as Greater Daemons and maybe Spirit Hosts as Chaos Spawns?
Really it is just a case of making sure your opponent knows what's what and is okay with it if you plan to field this against unfamiliar players.
Nonsense is our Salvation