But of course, I am the leader of the Adeptus Gramaticus anyway
Hmmm, I'd have to go with Cockatrice for basic daemon (Flamer of Tzeentch) but instead of having Stone stare swap it with Chaotic Fire spray. Warped blue birds flying around shooting fire from there eyes. Tzeentch would be proud.....
As for the Greater Daemon, I'd think that Griffons would fill that position well (Atleast a warped up ferocious Griffon; that way we can use normal Griffons for other things, perhaps as the normal troops for Thousand Sons but that's a different idea). Have them stand on there hind legs, give them a staff, blue feathers, and warp'em around a bit and you'd have a pretty good Greater Daemon.
Edit: I'll go copy and paste it to the other thread, sorry.