I really doubt this, tbh. There's no way at any point that they'd have been expecting to be able to get Eccleston back for a full role like this given history. And it's entirely possible that part of the reason he turned it down is because the only thing they asked him to do was the regeneration scene at the end.
Well I'm not saying the part was explicitly Ninth Doctor, it could have been slightly more vague at the time where it could have gone either way. And has been said a couple times before, Hurt was only hired less than a week before filming began.
My thought on it is that it was originally conceived as a Ninth/Tenth/Eleventh story, with the former being changed somewhat from Ninth to War after Eccleston turned Moffat down. It's hard to imagine that Moffat would have deliberately shot for a Ten/Eleven/new guy story right off the bat.