Joffre-class construction and American carrier transfers

Would France receive American fleet and Independence-class carriers as replacements if the Joffre class had been built?

No; a completed Joffre class would remove the need, while France without those ships could welcome the American transfers.

Foreign assistance fills a capability gap rather than automatically supplementing an existing French program. If the Joffres enter service, France has less reason to accept the proposed replacements. Without them, the American carriers become a useful and welcome substitute.