Why wouldn't Louis live longer? He died 3 months AFTER he wed Mary Tudor. Of exertions in the bedroom. Give him a wife who DOESN'T look like Mary does and maybe he'll be...less enthusiastic. (In a discussion where he wed Bona Sforza it was suggested he'd last until 1517/1518).
That François would. It's been agreed since 1505/1507 , so barring Claude predeceasing her dad, such a match WILL happen.
I do NOT want to be the canon lawyers who will have to deal with THAT particular headache. Under church law, Eleonore would be François' mom (not mom-in-law). Don't you think João III would've tried this once his dad died, rather than wait for Eleonore's younger sister?
Plus, the minute Eleonore remarries she'd lose the regency for her son (if she has one). No kid or a daughter, means that Eleonore gets sent back to Karl V (like Portugal did with her OTL). OTOH if she HAS a son, François d'Angoulême is the biggest enemy - this kid is the James V to his duke of Albany as it were - and François has Brittany not to mention the Angoulême lands PLUS he's Connetable/Lieutenant of France. I DOUBT he'll slink back to Amboise or Nantes quietly.