[quote=@Lugubrious]
If Sapphire said something about Pops experimenting on people, that would have been inaccurate.  The humanization procedure would have worked, the main conflict was that it would have been unethical/White Fang-angering/a bad idea to do so.
[/quote]

That's what Oswald was told. But, how could Pops be sure the procedure would have worked without an actual Faunus test subject? 

Not trying to be snarky, I know as GM that, in-universe, you'd have had it work, but how could HE know it'd work?