There's a problem here:
After her marriage to Charles VIII in 1492, Pope Innocent VIII issued a bull in which he both validated her marriage (given some earlier impediments, including past precontracts on the part of both spouses) and granted Brittany to whichever spouse outlived the other.
While this mattered little, as Anne did outlive Charles, the bull also contained a clause in which Anne promised to wed Charles' successor if their union was childless.
Now, this had two basic effects:
1) it essentially bound Alexander VI by the precedent set by his predecessor, to do all he could in the situation (though conceivably he could have ignored this earlier decree)
2) more importantly, it would cast into doubt questions as to the validity of any other marriage which Anne made, as it could be argued that she was under a de facto precontract, regardless of Louis' marital status. And while she could ignore this, the French would not be apt to do so, given the desire on Louis' part to gain Brittany.
So, you'd have to move back the POD. Either Pope Innocent will have to refrain from including that particular clause in his bull recognizing Anne's marriage to Charles, or, you'd have to have her wed someone else entirely than Charles VIII
Just a suggestion: Anne was married by proxy to Emperor Maximilian (newly widowed after the death of Mary of Burgundy) in 1491, in an attempt to secure an anti-French alliance and protect the interests and independence of her duchy. The marriage was later dissolved before it could be celebrated in person (thanks to some cooperation on the Pope's part), though, and the duchess married to Charles instead. That could present a very useful POD. Just an idea.