I think the optics of this aren't great. You ask someone to copy their voice, they say no and then (maybe coincidentally) you release a voice designed to sound very similar. Legally this may well be fine but come on, didn't anyone think this might make them look bad?
Sure, but to me it looks bad from the other perspective too if this is made into a problem. A person's natural voice is their voice and some celebrity should NOT be able to dictate how it is used.