For clarity, I agree with much of what you're saying, but I'm not sure I follow with the bit about Wandale and Ozigbo. 'Replace' as in take his carries, 'replace' as in fill the role he had?
Either way, I don't think it's accurate to characterize him as a Zig replacement and I don't think that's what the coaches are looking for, either. Wandale is barely 5'10" and probably won't sniff Zig's playing weight. I think Mills is more of the guy you'd look at to fill Zig's role, assuming he can get on campus.