Looks like I forgot to comment here a month ago when I first saw the frame pictures - but better late than never...
Certainly, looking at the pictures these seem to be nice sculpts, and with a lot of conversion potential. Unlike many of the other Frostgrave plastics, these seem to be rather heavily armoured, which to me seems a bit surprising for demons - though not having read the book I do not know what is their background.
However, they look like an excellent source of well-armoured mutant humans, beastmen, half-demons etc. for a variety of settings. For example "oldhammerers" might want to consider using these for WHFB 3rd edition Chaos Thugs with the appropriate chaos attributes.