Regarding the story of "Wolverine was originally meant to be a mutated wolverine," the story itself is true, but Len Wein has been mis-attributed by many folks (including by me) as being involved in the idea.
From the late, great Dave Cockrum:
Stan Lee himself put the kibosh on it. We were going to suggest that Wolverine was not a human at all, but a mutated wolverine. There were remarks in the storyline at one point where somebody was assessing Wolverine and saying, "I'm not even sure he's human" or something like that, which would have led up to it. But Stan found the concept disgusting.
Here is the scene in question, from X-Men #98...
The confusion comes from the first time Cockrum discussed it, years earlier, in an interview in 1981 or 82. It came up in connection to some unused ideas Len Wein had for Wolverine, and then Cockrum went into the mutated wolverine idea, and ever since then, it has been conflated that Wein was involved in THIS unused idea, as well (and I think that's reasonable enough - if you say "Wein wanted to do this, Wein wanted to do that" and then you follow with "we were originally going to do this" then it seems like it is Wein who's being discussed - and then in the future, Cockrum just refered to the idea as something "we" were going to do).
But that's not the case.
Apologies to Mr. Wein for the mis-attribution!
Thanks to Scott Beatty for the Cockrum quote.
When you read this story in the book, just imagine Cockrum's name in place of Wein's. ;) If we ever get a new printing, I'll fix the error.