In Mike Cohn's example about the surgeon and the kid, I'd go through the following approach:
Estimate with the brain surgeon estimation, but making explicit that the brain surgeon will be training the kid during the process.
The main issue you'll have will be the planning, as you still have the constrain of your Swagger hero, having to train the other guys. As Mike says, brain surgery can be done only by brain surgeons, but you may train quickly more brain surgeons.
Think about this: you don't want a team in which only one of your guys is the hero (you'll have a bus factor of 1, and that's never good), you want A TEAM of people being able of working in the different technologies you use. Of course, you'll have issues whilst the training, as you explicitly have a constrain of one developer having to do so, but if the tasks are done by two developers, one of them actively doing knowledge transfer, you'll reduce that knowledge gap quickly, you'll build a better and cohesive team (having team members helping each others is a good way of doing that), and at the end you won't have neither big differences nor bus factor of 1, being able to deliver much more and with less risks.