Swift is working on their own blockchain tech, called Hyperledger. They already have major banks like Wells Fargo and BNP onboard with their proof of concept.
https://www.coindesk.com/swift-selects-hyperledger-tech-cross-border-blockchain-test/
Swift intends to develop their own blockchain tech, then use Chainlink decentralized oracles to provide input to the smart contracts. These are not hypothetical, they have been in the works for years. You are right that Swift and Ripple dislike each other, and are going at each other's throats. However, Chainlink tech does not begin nor end with Swift and the finance industry - they are about linking smart contracts with traditional data sources in general, no matter what industry.
No one knows who will come out on top re: Swift vs. ripple. Conversely, I can say that if Swift succeeds, it's bye-bye for ripple. I would give a bit more credit to Swift