I'm sorry to hear you had such an issue.
Is the problem with the black ravenwing scheme how other colors look over black? What was your process? I ask because I think black is one of the easiest colors to use because it typically just covers everything! We just need to be careful when going back to pick out other colors.
Usually the other tough part with black is highlighting it correctly to add a satisfying contrast to an otherwise dark model.
I just google searched "dark gray ravenwing" and fond number of options. Here's a decent contender.
This person painted everything black and then did a heavy gray dry brush to pick out all the edges and raise other overall lightness of the model. A totally acceptable approach. Another easy method would be to basecoat the models a medium/dark gray then do several dark washes (nuln oil, etc.) over the model to create the shadows, and do a light dry brush with a lighter gray over that to highlight the edges. In either case you would still need to go back in and pick out the accent colors, trim, metals, flesh, etc.
Does that help?
[edit] Oops, forgot your other question. I'd soak any model which needs to be stripped in simple green or dettol and use a dull knife to pry apart the joins in the model. Did you glue the models or just snap-fit and paint? If they are just snap-fit then you should be able to pop them apart easily. Otherwise you may need an eXacto or other sharp craft knife and need to cut the joins.
Is the problem with the black ravenwing scheme how other colors look over black? What was your process? I ask because I think black is one of the easiest colors to use because it typically just covers everything! We just need to be careful when going back to pick out other colors.
Usually the other tough part with black is highlighting it correctly to add a satisfying contrast to an otherwise dark model.
I just google searched "dark gray ravenwing" and fond number of options. Here's a decent contender.

This person painted everything black and then did a heavy gray dry brush to pick out all the edges and raise other overall lightness of the model. A totally acceptable approach. Another easy method would be to basecoat the models a medium/dark gray then do several dark washes (nuln oil, etc.) over the model to create the shadows, and do a light dry brush with a lighter gray over that to highlight the edges. In either case you would still need to go back in and pick out the accent colors, trim, metals, flesh, etc.
Does that help?
[edit] Oops, forgot your other question. I'd soak any model which needs to be stripped in simple green or dettol and use a dull knife to pry apart the joins in the model. Did you glue the models or just snap-fit and paint? If they are just snap-fit then you should be able to pop them apart easily. Otherwise you may need an eXacto or other sharp craft knife and need to cut the joins.